I don't remember Jackson as a Ram because I started following them in 1978 right after he left for New England. But if you look at his numbers during his prime- 1969 through 1979- he led the league in receptions, yards, YPC and TDs over those 11 seasons.
From '69-'72 as an Eagle he was 2nd in receptions and 1st in yards. Then as a Ram from '73-'77 he was 8th in receptions and 4th in yards.
So yes, just looking at him in his era he was a HOF candidate. He was on par with someone like Fred Biletnikoff.
