Almost certain (in fact forget the almost) that he didn't.
Here is a link to a times online article. All the other players featured who did get capped have it mentioned in their bit. No mention of JF getting any (and the fact he wasn't Welsh also makes me fairly sure).
http://www.timesonline.co.uk/tol/sport/article584409.ecehttp://
For the clickless:
Sheffield United had spent two seasons in the Second Division without setting the world alight and there were worries that they might have a long wait before returning to the top flight.
They need not have feared. During a rollercoaster season in 1970-71 they secured promotion with a side whose attacking flair gave the Blades a cutting edge, finishing second to Leicester City. But the campaign was not without its tense moments. They were two down with two minutes remaining away to Queens Park Rangers and salvaged a draw, and scrambled a late winner against Millwall. John Harris, their manager, had made a rare excursion into the transfer market to secure Trevor Hockey from Birmingham. His role in the midfield was to win the ball and give it to Tony Currie. Everything else flowed from there. [The numbers refer to a photograph, which is not carried on the website.]
1 Ian MacKenzie Still a teenager at the start of the season, MacKenzie joined the club as a junior but was only ever a fringe player. He made 45 league appearances in seven years, was loaned to Southend and then sold to Mansfield, where he had more success in their defence. He runs a pub in Peterborough
2 Len Badger A dependable right-back who was the club captain, Badger signed as an apprentice in 1962 and in the next 14 years played in 458 league games. He won honours at schoolboy, youth and under-23 level for England before finishing his career at Chesterfield. He is a publican at the Fox & Goose Inn at Old Brampton near Chesterfield
3 Bill Dearden The promotion season was Dearden’s first with the club and he proved a big hit despite struggling with injuries. Having played for Oldham, Crewe and Chester, he spent nearly six years at Bramall Lane, playing in 175 league games, scoring 61 goals. He went into management and coaching and is assistant manager at Blackpool
4 Tony Currie A talented midfielder whose flair and passing skills played a huge part in Sheffield United’s success during his eight years there. Currie played in 313 league matches and scored 55 goals. He won 17 England caps and had success at Leeds and QPR. He is a community officer at Sheffield United
5 Geoff Salmons The left-sided midfielder advanced through the junior ranks to play in 180 league matches for the Blades. He had a fine left foot. Salmons joined Stoke after eight years and was loaned back to United for a month in 1977. After finishing at Chesterfield he moved into the hotel business and runs the Marr Lodge in Doncaster
6 John Tudor Having learnt his trade at Ilkeston Town and Coventry, Tudor joined Sheffield United in November 1968. Despite scoring 30 goals in 71 games, he was sold to Newcastle United midway through the promotion season with David Ford and John Hope moving the other way. Tudor had success at Newcastle, scoring 53 goals in 164 league games. He moved to the United States, where he is coaching in Minnesota
7 John Flynn A powerful defender who joined the Blades from Workington in the summer of 1969. He spent nine years at the club, playing in 190 league games. He then moved to Rotherham and is now a probation officer in Worksop
8 Dave Powell The Welsh-born central defender earned his spurs at Wrexham before joining United in September 1968. He played 89 league games during the next four years. Powell won 11 caps for Wales and joined the police in Bridgend after retiring from football in 1974
9 Graeme Crawford Born in Falkirk, Crawford signed for Sheffield United in 1968 as cover for Alan Hodgkinson, but failed to make the grade. He played only two league games during three seasons before joining York City, where he kept 11 consecutive clean sheets. He is a non-league coach in Derbyshire
10 Alan Hodgkinson After arriving at the club in August 1953, he was finally coming to the end of his tenure in 1970 and the promotion season was his last in a remarkable spell. A technically superb goalkeeper, he played in 576 league matches in 17 years and won five caps for England. He then became a leading goalkeeping coach and had spells at Rangers and with Scotland. Hodgkinson coaches at Oxford United
11 Frank Barlow A Sheffield-born defender who won caps for the England schoolboys but failed to reach similar heights at senior level. Barlow spent seven years at Bramall Lane, playing in 121 league matches before moving to Chesterfield. He is assistant manager at Nottingham Forest
12 Colin Addison With successful scoring quotas at York and Nottingham Forest, Addison was signed by Arsenal in 1966 but lasted little more than a season before joining Sheffield United. During the next four years he scored 22 goals in 94 league outings. He has had mixed fortunes in a long management career and was recently in charge at Forest Green Rovers
13 Paddy Buckley Injuries robbed the Leith-born winger of a promising career after he joined Wolves from Third Lanark in 1964. He signed for United in 1968 but in four years made only 15 first-team appearances. He is a coach in north Derbyshire
14 Alan Woodward A wonderful winger in an attacking line-up, Woodward was a one-club veteran who won international honours for England at youth level. He spent 15 years on the right wing at Bramall Lane, playing in 539 league matches and scoring 158 goals. He lives in Oklahoma and works in the maintenance section for American Airlines
15 Eddie Colquhoun His fine reading of the game in defence was a bonus to the club after he joined in October 1968 from West Bromwich Albion. Capped nine times by Scotland, Colquhoun spent 10 seasons at United and played in 363 league matches. He runs a post office in Conisbrough in south Yorkshire
16 Gil Reece The Welsh winger scored five goals in four games as United’s push for promotion gathered steam late in the season. After joining in 1965, he played in 210 league matches and scored 58 goals. Awarded 29 caps for Wales, he had a plumbing and heating business and then ran the Clare Court Hotel in Cardiff. He died in December 2003 at the age of 61 after a long illness
17 John Barnwell A veteran midfielder who had enjoyed success with Arsenal and Nottingham Forest, Barnwell joined Sheffield United in April 1970. He played in only nine league games before retiring. After a career in management he is chief executive of the League Managers’ Association