From what I'm reading the numbers on back should have more letters? Is one of these a serial # or are those inside? An older gentleman has asked me to sell this & some other things for him on ebay, which I'm happy to do, but I like to be halfway knowledgeable in my descriptions. Also I'll be happy to share the ebay link here if any one is interested when it goes on auction, and that's permissible. I've read that one shouldn't post photos of serial #'s, is that true? Basically just asking what to call this model, saw similar being called Divers? and is it early '90's? Thanks in advance!