Need help pn spotting fake or real vintage Blancpain Fifty Fathoms "Aqua Lung" no radiation

Hello Omega forum!
This is my first time posting here after lurking for a while not being a member. Decided to become a member, because I have no idea about this one and need help on spotting fake

Recently I stumbled across someone selling vintage Blancpain Fifty Fathoms, since I don't know much about this vintage Blancpain, I have 0 clue on how to spot a fake one. Luckily the seller is brave enough to share detail picture of the watch. Would be grateful if you guys can help me on this one, since if it's real , this will be the first Blancpain I get.

The only thing i know about vintage blamcpain is the movement is supposed to be uttilitarian with few to no frills and the case back supposed to have a janky setup like this one. Other than those 2 I'm completely in the dark here. Would appreciate it if some one can help me with this one. Thank you

Thank you so much for the quick reply, yeah I also have little bit of suspicion about the dial and the bezel. Would take your respond on my mind next time i come across another one. Thank you !