Hello Anders, and welcome to the forum.
The suffix letter on your Luger looks like the letter "q". See the key on our site at:
http://lugerforum.com/lugermarkings/suffix.html
The full serial number would be "1379
q" (S/n corrected per pictures below...)
This Luger looks to be in a very high condition. It was made by DWM in Berlin. It looks like it's marked in the Commercial manner.
Is it in 9mm Luger or .30 Luger Caliber?
Are there any proof markings on it?
If it's a post WW-I commercial Luger, and falls within the Alphabet Commercial time-frame, the "o" suffix would occur in about 1924-1925 (based upon the ones we have here in the USA from that period).
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Igitur si vis pacem, para bellum -
- Therefore if you want peace, prepare for war.