The "Nds" in Circle shows that they have been bought by and have been in service with "Niedersachsen" state police. The BMI proof stamp seems to confirm that.
In theory they could have been spare guns that got sold off when Niedersachsen changed to the SFP9 or have been in stock with HK but already marked when the contract ran out.
But I see different amounts of wear:
70890 - slight amount of holster wear on the front of the slide
71931 - seems to have a small amount of "wear-patina" (side of squeeze cocker and markings for example), not sure if this could come from storage (in the box)
69288 - no holster wear
72230 - I see a decent amount of (matching) holster wear on the front of the frame and slide
Anyhow, any german proofmarked gun is not "unfired" anyways, as they are required to be fired with a couple (usually 3) high pressure proofing rounds and then at HK undergo a function and precision test that can take between 10 and 20 rounds depending on type of gun and customer requirements (police testing procedure may differ from civilian test protocol).
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