Hi, Gallen!
Just thought that that stamp looked awfully familiar, especially the last bit of it.
I have just been down the basement to the lockup and made it back upstairs (the hard part, believe me) and, right now, I am sitting at the kitchen table and looking at PLY 3692.
PLY 3692 has been hand-stamped with the PLY, same as yours, my lettering being very close together and rather straight where yours are more irregular, but the punches are the same ones. The number on mine also is punched in the same location as yours, but in a different, slightly smaller set of punches. My bolt is pinned, too.
The stock has been scrubbed of original serials, etc, there remaining only the slightest evidence that there ever was something there. I'm pretty sure that with normal methods it would be impossible to determine the original number, but you never know what UV might show until you try it. The stock, also, is very like yours except that it is missing the top handguard and the wood from under where the band used to be; it was cut right at the front of the band and reshaped. There is polishing on the top of the barrel to show where the handguard was for some time while the rifle was in use. Stock also has been reshaped a little and refinished, likely at the time the handguard was removed. Either Bubba or his cousin has drilled a couple of holes in the barrel to attach a "real" rear sight, that terrible old Ross Battle Aperture Sight obviously being so inferior. But he decided not to go this route and then the tapped holes were plugged with Allen-socket-head screws. Thankfully, the original rear sight remains attached and in good working condition. This one also has no front-sight hood, so we're in the same boat there. Barrel is 24-1/2 inches, so is same as yours.
(With all this inspection and poking and prodding going on, the poor thing is shaking in terror. It's afraid that I might sell it, then it couldn't spend time reminiscing with all the others! Couldn't do something like THAT, of course!)
Barrel is stamped with the LC stamp, meaning the chamber has been reamed, major reason I haven't taken her out to the range. Do something about that, right quick.
And, of course it has that beautiful little Canadian inspectorate stamp, crossed flags and Crown and DCP. I wish somebody would do up a poster of that, put on all the Canadian-built military small arms (including the Cooey 82), full-colour with the big DCP stamp in the middle. Get a hundred thousand of those out there and up on walls and people might start to think differently about our "non-military" past. Put production figures under each picture, too! You can't argue with a few million.
Anyway, the reason I was querying your exact stamp was that I knew that I already had a PLY, so I thought it would be nice to compare the two.