Police Luger Unit Mark

[alanint]

I was just shown a nice police Luger with the following Unit Mark;
L.Ar.185.

This appears to be a Wiemar era commercial Luger. The only marks on the gun are the following;
Proof: Eagle, Wa, Eagle. Eagle Proof on Barrel
Serial number is 3313 u on frame and barrel. "13" on last toggle back. Toggle axle marked "13". No nitro proof, no manufacturer on toggle, no chamber marks. Matching wood bottom Mag 3313 (no u) and number 1

Sear safety present, magazine safety removed. Wood grips look correct, period but no marks inside
Finish is original, (nice halos on barrel and unit marks) with only typical holster wear and some additional wear on the sideplate. Straw is strong on ejector, takedown and trigger, less so on safety but all appear original.

Initially I need an answer to the unit mark. This gun will be for sale but I am looking for an honest valuation as soon as I get photos up.
Thanks, gents!