I'd say you were about right. It sure is hard to judge them ain't it?
I am terrible at judging bears, but I think your close on the weight. The straight on view as he was approaching you shows he's got some size through his neck and shoulders. Like you said, he has a belly on him as well. That's what a month straight of acorns on the menu will do. I was hunting at around 3400' Friday evening and the acorns were still dropping like crazy every few minutes. Reds and Whites!
That bear is hardly over 100#'s. I've helped pull 100's of bears out of the woods and most folks bigeye bears like Roland Martin does a 3 pounders saying "that's a giant 5 pound bass".
The only true way to judge a bear is how is it going to square. Heads are genetic. Some areas just have big headed bears. Other places have big bears with not so big a head. Weigh most times than not just means a fat fall bear. Not unlike a fat lazy person who has a lot of food handy . But a huge guy doesn't have to be a fat guy and most times ain't. Bears are the same way.
I would have guessed way over 100 lbs, but I don't have much experience with bears yet. I passed up several this year that were borderline. Definitely do not want to end up paying a fine for an undersized bear.