I've been collecting Bally games for 20 years. Have probably owned close to 100 of them. This is a tough call because of the backglass and it was described as partially restored. And the partially restored can mean anything to anyone. But it also says original condition.
In my honest opinion you are being a little nit-picky on some of the stuff and you can see in the picture of the backglass that it's flaking. Not the greatest picture but it's visible. I would have asked for better pictures as soon as I saw the one posted. Also if paying that much for a game I would have asked for another dozen or so pictures.
If it was a different game then yes I would have expected better. You are pretty much paying for the title not the condition.
My outcome would be
1: Seller should have pointed out the backglass had flaking.
2: You should have asked for many more pictures.
So I see both parties at fault.
PS. Man I would love to own that game!!!!