False - More to follow; but for now let it suffice that we have several dated to the mid/late 1930s, with the "PK" under the finish and the "N" marked receiver.
1] These two show a black-parkerised interior of the bolt-channel; the upper is MAC 1934, the lower, MAC 1938
2] Upper is #AC 91496, "N" to barrel and receiver, beech stocks cartouched to October, 1934, barrel to 7/1934. Lower is MAC 1938 barrel, "N" for replacement, but not "N" marked upon the receiver, and will not chamber the 'N 32', # BD 15267. Stocks are 'Black-Walnut' and the cartouche is 'hors de combat', if I understand that term correctly.
3] From the top and confirming the above. Of note is the fact that both stocks were never cut for the cleaning rod.
4] the third example is not worth the bother, and I found it in one of our scrap-barrels as an uncleaned house fire victim, though still on the 'books'. The barrel is MAC 1931, but the bottom flats have been re-marked, over the "E", as 1.33, the carthouche is gone.
Alamas and Vivelacola have provided more than I could ever hope to. A search of their posts will be worth your time.