Sorry, but it is not one I would care to own. IMO this one is a crude fake. I agree with Ian that the detail is weak and it shows the flaws associated with a crude casting process.
The maker marking on the reverse is bogus: a poor attempt at copying the marking of Moritz Stumpf & Sohn. The marking is inaccurate, ridiculously too large, and it looks like modern engraving. Besides that, I believe these Danzig Faithful Service Crosses were not maker marked. But, on the possibility that some may have been marked, the marking would be small, stamped (not engraved), and placed on the reverse of the lower cross arm.
Note details in comparison (lion's mane, oak leaves, dots surrounding the centre all individual and not so tight they form a continuous string, +many more):
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