Esteemed OF member UWSearch previously documented the rare "grooved" version of the 1170 bracelet in his now classic reference thread: https://omegaforums.net/threads/fro...ge-seamaster-and-speedmaster-bracelets.45883/ Here is a photo of the grooved non-trapezoidal clasp: Here is a photo of my own clasp currently mounted on the 1170 bracelet of my 166.073 "Deep Blue." I recently stumbled upon a "hybrid" version of these two clasps: one without the engraved "30," but with a differently designed grooved outer clasp. Is this a rare previously undiscovered variant of the 1170?
Try and find another example with that outer clasp. If you can't it's either an extremely rare version or it's had a different part swapped in. I know what I feel is more likely.
I understand your skepticism, but in the photo, there are two “rare” outer clasps that are completely identical to each other. What are the chances of that happening?
Nice, I found one!!!!! An identical example sold on chronocentric 2 years ago! http://www.chronocentric.com/forums/chronotrader/index.cgi?md=read;id=55586
But the two 'rare' clasps you refer to are different to yours? They could be genuine rarer versions, they could have been repaired with non original clasps. You can only go on what's most likely based on the evidence out there.