I have looked this up on the Omega website and it states the case is 35.5mm, seller says it is 38mm without the crowncrown
I think the website is wrong too, the dial is roughly 36mm wide and there is about 2mm between the dial and the crown of case making 38mm. The case is slightly thicker on the crown side if that makes sense - hence where the 35.5mm/36mm measurement could be coming from.
Do you think the watch looks right, I am tempted to have a bid on it, there are no pictures of the movement seller says it is a 3220, which is what the website says, but if I can get the info anybody can
I can't guarantee how it performs and all but from the looks of it, it has all the right parts and is authentic on the surface.
For 2.5 months, I looked everywhere online for a Speedmaster. In the end, I followed ΩF advice and sent a PM to @Kringkily. Not only did I get the watch I wanted but also was confident that it was authentic and in good shape. I am not sure I would have been as confident in my purchase had I bought from eBay or elsewhere. If you PM him, he should be able to locate one for you.