The starting weight variables have been listed under Law 2 for some time but interesting to note comments from Frank McLintock amongst others, although I wasn't there so can't comment further the article is here
https://www.thetimes.com/travel/des...as-like-being-hit-by-sonny-liston-80p8kzjp56b
"The change in the balls came in the 1970s when synthetic materials began to be used instead of leather, ensuring that the maximum ball weight of 16 ounces did not increase during a match when the pitch was wet. Fifa, the world governing body of football, now insists that balls are non-absorbent"
Although this is over the head-injury lawsuit, so is going to be biased towards balls being heavier and gaining weight, there are a few other sources, that did say the outer coating used to rub off easy (all played with one of them against a garage) and especially in winter they were heavier at the end of the match than the start.
The point and it's not a negative point, it's more, I wonder in the modern game using the modern boots, pitches and balls, would Keith Edwards be one of the best players to have played the game if he was retiring now rather than in the 90's.