Welcome!

[space]

It is a factory stamp. I believe it means that it was made at the main Radom factory (#11)

All P64's I have seen have it.

[abwehr]

Yep, "Space" is correct; it stand for the Radom Plant!

[easternbloccollect]

Can anyone tell me the significance of the circled no. 11 on the slide?

Hawkerjim

I just joined the forum. I collect Communist Bloc/WWII military surplus rifles. I have recently decided to add handguns to my collection. The Mosin-Nagant M44 that was manufactured in Poland also has the number 11 inside an oval on the barrel shank. This symbol is the country code for Poland. (Hungary's code was: 02.) Although I have not seen a P-64 up close, what you described sounds identical to the code on the M-44.