Back in 2010 I bought a stripped upper and lower to do a pistol build. The lower is registered as a pistol but I only shot the completed pistol once and a couple years later disassembled it and sold off everything but the upper and lower. I am thinking about building a rifle out of them. Any legal pitfalls to worry about if I do that or should I sell the set to someone who wants an AR pistol and just pickup a new set?

TIA!!!

No worries about making it a rifle after being a pistol first. You can make it back to pistol as legally and easy as removing the rifle stock BEFORE putting the pistol upper back on.

Good news. Thank you!