With the FAL barrel so easy to remove, just pull it and have it lathe threaded.

Most die threading kits have a solid pilot that is than less then ideal for the last inch of bore, plus the threading kits are not know for keeping the threads straight/parallel with the bore as well.

Plus the fact that you are going to be running a FS on the barrel, can have the muzzle 11* crowned as well (works best for barrels that you are going to do a lot of scrubbing on with a bore brush).

Bluntly, a threading kit will run you in the $70 range that you may only use one, while someone like Adco only charges around $35 to thread a barrel instead.