. . . until now? I mean, you even told me about it, and on top of that, I was told last week by an Omega staffer that the traveling exhibition was at the Topanga Mall Omega boutique. (I intended to drop by and actually had camera in hand that day, but wasn't able to make it.)
The primary distinguishing characteristic of vintage Seamasters, afaik, is that they all have screw-in backs (or, as with Seamaster DeVilles, monocoque cases). Here's an early ref 2576 chronometer from the first production run in 1949 . . .

. . . that doesn't have Seamaster script on the dial. I'd wanted one since forever, and by sheer luck found this example locally last year, but recently traded it back to the person from whom it was acquired. (So yes, a SM chronometer is back on my wish list.)
As blomman mentioned, this . . .

. . . is the original Omega diver ca 1932. I'm not sure of the depth rating, but they were intended to be used by deep-sea divers. Remarkably, they were delivered with deployants.
This is the SM diver that I'd add to my collection anytime, an uncommon ref 165.027 . . .

. . . ca '67. Cal 552 automatic; there was a manual wind version fitted with the cal 601, too - ref 135.027. These haven't gone off the deep end yet - they can still be found at reasonable prices.
This SM would be more commonly known by its nickname . . .

. . . the Anakin Skywalker (ref 145.023, ca early 70s). Yes, there was a Darth Vader, too! Way cool with serious wrist presence, like most of its Omega cushion-case contemporaries.
The ref 166.068, aka . . .

. . . The Banana. (There was a grey dial variant, too; it was called The Poppy.) Issued to the French Navy in the early '70s, if memory serves correct.
Believe it or not, these split second timers . . .

. . . listed for close to $100K (not a misprint!). The story I was told is that a set of movements originally created in the early '30s for the first Los Angeles Olympic Games were uncovered, and Omega decided to issue them for the 2010 Winter Games in Canada. I took this photo in January 2010 . . .

. . . but didn't save any movement photos. Regrettable, 'cause the complexity and finishing were on a par with modern Lange.
Sorry to have missed the exhibit!
Art