GM door locks, how interchangeable are they?

I've had a to do list on the Opel and its finally getting relatively short. It's down to the last few things on the maint/restoration list.
-Front windshield (Trying to buy)
-Various leaks (parts on way)
-Weather stripping
-Door locks/handles

Today I attempted to cross off that last one, I managed to get all door handles on the car 100% operational which is satisfying. However the drivers door lock wont work and I don't know how I plan to fix it, I found a small number of pages that were reasonably useful on the opelgt site, a manta owners site (control F 'door locks'), and I found out that my car shares parts with a gen 1 Vauxhall Cavalier while shopping around.

Also during my shopping around I noticed that a lot of USDM GM door lock parts look VERY similar to mine. Is there anywhere I should look to confirm or deny this?

Look for a part number stamped on the actual part. GM's pretty good about that.

Although with the rust problems in GTs, I've gotta think there are lots of lock donors out there.

dammit, i just put the doors back together, tomorrow AM i'll pull it back out to update.
i got an ascona, unfortunately the GT part i probably could use i dont need :( (afaik)