There are multiple companies out there that make FAL-clone recvrs that you build up using FAL "parts sets" you acquire - L1, Argy FALs, Imbel sets, et al. Look for Entreprise, Coonan, DSA, NOS Imbel recvrs. Not sure if Hesse makes FAL recvrs anymore...
These recvrs are being made for both "metric FALs" and "inch FALs" (UK and commenwealth L1 FALs), so be sure ask which recvr to order to your dealer.
Meanwhile, Entreprise and DSA make complete, ready to go, USA-legal FALs.
Century will be your cheapest option for a complete USA-legal FAL, but as always - look it over carefully. Many folks have had great luck, some hand them over to a "FALsmith" for final tweaking.
Good luck - biggest issue with FALs; ammo $$$ !!