At the LGS doing a transfer on the stainless USP .45 I kinda got "stuck" with off gunbroker this evening. I was checking out the candy in the HK cabinet passing time and saw what I at first thought was my gun in the case for everyone to FF. I asked to see it and realized it wasn't mine, but a 06 dated full size that had been NP3 coated. Seemed in good shape, though shot a bunch since the coating was showing wear on the chamber. I was just checking out the finish when I saw it, right next to the HK engraving on the muzzle. It almost looked as if it belonged there since it was so close and inconspicuous. A small circle with an offset JS inside it. I didn't think to take a pic till after I had left. Maybe I can get a shot when I go back after my 7 day wait. I've never seem anything like it and assume it was added by the owner or whomever did the refinish. Any ideas?