My third FAL, an "ARS" StG on Imbel, built by Mark Graham should ship in a few days.
There is another "ARS" build on the Marketplace of FALfiles: "Imbel on Coonan".
MG never used an inferior upper receiver. The only reason I didn't consider it is because I already have an Imbel FAL.
The seller "packingvol", who lives in east TN, has documentation to verify who assembled & tested his.