Simpson Ltd has a post-war cut away, if you want a price comparison:
https://simpsonltd.com/german-factory-cutaway-luger/
Also a WW-II Mauser:
https://simpsonltd.com/mauser-1940-luger-cutaway/
Since the one you are asking about was unit marked, it's likely that it was acquired and issued, but that an armorer did the cutaway for some reason. Cutaway Lugers were also salesman samples, but the factory would not be adding unit markings. That happened after they were acquired and issued to various units.
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Igitur si vis pacem, para bellum -
- Therefore if you want peace, prepare for war.