Farmingdale is the first plant where Rohrbaugh started producing guns and only a few were made there. They then moved to Deer Park, NY. The first ones, at Farmingdale, were made with blue carbon fiber grips (about 300) and no "R" prefix in the serial no. then Rohrbaugh switched to black carbon fiber grips with a few more blue CF's as well.
The Farmingdale's are rare and that's why a few of us wanted one, two, or............... of them.