Frank, thanks! Alas I don't have that book (yet) and finding such info on the net can be at times like searching for the holy grail using two coconuts and a megaphone...
From what I see, the proofs on the right side of the frame match DWM 1914-1918 proof stamps. There's a commercial nitro proofing (I think; N with what looks like a weird crown over it) on the bottom of the barrel above the serial; I'm guessing that was done for export purposes. I don't see any other proofs on the barrel, other than 8,8 and a very weird symol next to that, directly under the N marking...and of course the serial.
The breechblock has the proper eagle stamping....but I don't really know where else to look for proofs and other marks. It looks totally correct.
Also, I did find the number stamped on the take down lever; it's stamped on the bottom of it, if you hold the frame upside-down, you see the last two digits of the serial.
I have a feeling I could study this thing for months and I still wouldn't find all the markings on it
Thanks for all the help!!