That's a good idea I should do it for mine too. Last week I had contact with them about my 30 CH. I received production information in an email form, not an "Extract" certificate or anything. Do you mean the same? Or did you actually receive an extract/certificate?
It was in and Out of production - ~ 2008 -2010 I think - Not a big Seller - Also available in precious metal, Red Gold/White Gold, and MOP dial, also a Chrono version... All Apparently a Bust in Sales... Mr. Urquhart's theory, as he told me... " It didn't look like an Omega"... I think that lessen was well learned when you look at the current offerings...if they knew then what they know now, I'm sure it would have been a LE - like the Bull Head...
Could be sharper - but more black is impossible. Oh... edit. I have now got the right crown for it. Not installed yet though.
How's your Italian? The link below is pretty good. There is an example of the same model (ref. 7042, with cal 19AS), the earliest of the two-crown, super-compressor-type Longines divers that spawned the "Legend" reissues, around the middle of the page. I primissimi. Una rarità nella rarità. http://www.longinespassion.it/Longines_Passion/longines_diver.html