Engraved model 12-8.
Model 5-5 configured similar to yours.
I have a Viet Nam era divers knife and also an older (40's?) model 3 that has a riveted sheath that is rare as hen's teeth. Also a couple of "brown button" sheath knives that I would consider. Let me know what you fancy.
No pitting on the blades. I bought them both at auctions 10 years ago. I do not know who did the engraving. I'd be willing to sell at my cost. PM me your email address and I'll send you a copy of the 2009 receipts.