Only the HK45 and MR series are "manufactured" in the US. In "manufactured", it actually means that the parts, which are made in Germany are "assembled" in the US. With the HK45 series, the one difference is the receiver mold, which is actually poured and formed here. On the MR series, the one difference is the barrels. They come in as blanks from Germany and are finished here.
With the new US production facility continuing to mature, we should see more occurring in the future for US production.