They look better there, because he is hitting the pose extremely well. Mike isn't hitting it as well. If you look at other pics in this thread Mike and then probably Tinnerino had the best delts. Arnold the best chest for sure, best biceps, then Coe, Back was one of the best. He did have weak points, his triceps were not great in this show, and his thighs were bad at this contest. They didnt judge glutes back then, and no I dont want to look, I think it is a stupid body part to judge. Sorry but no way Arnold was at his best here, as Zane said m in that short of time, his strong points made it back..
Arnold is hitting the BDB pose better than Mike,just as Mike is "hitting" the back relaxed better than Arnold(he twists his arms to get the attention to his strong points-triceps,while Arnold stays completely relaxed).
Arnold had weak points,no one denies that,just as everyone else at this contest had theirs (narrow clavicles,weak chest,sticking out belly were some of Mike's).Yes,they didn't judge glutes back then,but if they did Mike's loosing it even more as his were jelly like soft...
As you said, Arnold definitely wasn't at his best,but he didn't compete against himself.He was still the best in that line up and that's what matters.