Maria was very nice on the phone, but she seemed surprised when I asked...
If you look at Rohrbaugh's website it is kinda implied that they do not make everything.
"Our firearms are designed with the use of CAD/CAM programs. CNC machines perform the manufacturing. Then each gun is then hand fitted and assembled in our state of the art facility. The materials used are of the highest grade, including quality stainless steel, 7075 aircraft aluminum, G-10 grips and Wolff springs."
See how it says that "each gun is then hand fitted and assembled in our state of the art facility." They only say that the guns are assembled by them, but do not say that they manufacture the actual parts.