First, some states don't recognize an 03 FFL, period. So if you sell a gun to another 03 FFL holder you both may be individuals under state or local law and have to jump through whatever hoops may be required.
Second, as a C&R holder, you can sell guns to anyone as long as you do it in accordance with federal and state law, the same as if you had no license. You have to record sales in your bound book. There is a trap, though. If you buy bunches of guns under your license, and sell bunches of guns to non-licensees, BATFE will certainly say you are a dealer. The C&R license is basically intended to let you purchase guns for your own collection and to trade guns with other collectors to improve your collection. It is not intended to allow you to buy and sell hundreds or thousands of guns a year.