I went to the LGS where the owner had a trade-in G30 - Gen3. I have a G21 and G30S and I have wanted a G30 for a while. Actually I wanted the G30 when I got the G30S. I was glad I got the G30S. Now I have the G30 also. I'll shoot it in a couple of days. The SN has US added to the end, but only on the frame. The SN on the barrel shroud and the side of the slide are the same, but don't have US on the end. Anyone know what this means?