For me it's hard to tell from the pics apart from that base section that does look double the depth. I would like a closer look at the etching on the tank but even then would prefer to be able to compare mine to another original as well as yours just to be sure.
Mine has a small gap at the top of the tank section, always has done, doesn't bother me cos the top was so damn tight when I bought it that I had to post on here to ask for suggestions on how to get it off and new orings might sort the problem. The one I have is 0888, a potentially suspicious number that I would have wondered about had I not bought it from Vapist at vapefest and he handed it to me in person (and being from Manchester I have a natural suspicion of scousers but some of the have to be trustworthy right?)
I wouldn't pay for 2nd hand original gear unless I know I can trust the person and it's something that's a bit scarce and hard to get hold of (and I would always go with the person I trust even if there are 2 of the same item on sale and the person I trust is asking more money).
So, I'd say inconclusive given the evidence available, don't worry and buy from a trusted source next time so you don't have any concerns.