Pawel,
Do you know the history of this Luger? Where is it located? Having 1940 parts and 1934 parts all with the same #1 stamp is very odd to say the least.

i agree it is very odd, i think the 1940 portion might have been altered as the font for "1" is not the same...

Most likely scenario is that P.08 #1 from 1934 (K-date) got a replacement barrel and receiver somewhere down the line.

Interesting pistol, despite its condition.