I would say he was the greatest Offensive Lineman ever. Anthony Munoz, John Hannah, & Jim Parker have all held that distinction over the years but I believe Larry was better than any of them (and I saw them all play).
Allen was named 1st team All Pro and to the Pro-Bowl at 3 positions: RG, LG, & LT!
The only guy that surpasses him in versatility is Bruce Matthews who was a Pro-Bowler and 1st team AP at 3 OL positions as well but one of them was Center so I have to give it to him over Big Larry but Allen was the more dominant player.
IMO we have 3 players who were the GOAT at their positions: Bob Lilly, Larry Allen, & Emmitt Smith. Pretty awesome if you ask me!
I would rank Lilly ahead of Allen partially due to the position he played and also his longevity with the team.