. . . so, while the Swiss equivalent would be OT2909 (which truly qualifies for 'rare' status), this one has an American designation, 9082.
I'm not sure if the steel and steel/gold clad versions have separate reference numbers, but my guess is they're different, perhaps 9080 and 9081. NM kept separate records, so it's not worth ordering an extract from Omega.
There were ~ 75K - 100K cal 505 movements produced over a period of four years. I'd hazard a guess there were a hundred 505 Constellations to every Seamaster, and most of those were American issue. I've seen only one Swiss OT2909, and fewer than a dozen American examples since I've been collecting vintage Omega.
And that was a long time ago.
;-)