Thank you all for the information on your guns. It appears the gold "S" and the "P" suffix are out there on other guns. I am still looking for other examples with "FN" engraved on the tang. My theory on the O and U stamped on the trigger plate is that it was for the early single trigger with the selector on the trigger plate(see pictures).
The "P" is a mystery to me and I was curious if it was always on guns with "FN" on the tang. That theory is dead now. Here are some pictures of one of my guns with these items that I am trying gather data on. Please keep looking at your pre-war guns and if you have "FN" on the tang let me know.
IdahoBob may be corect in that the P may have to do with the choke boring. ""Live pigeon gun""???
Thank you
David
