Sorry for the VERY late reply - you'd probably have better luck on Shuff's Battle Tested forum, but all the BM59 boards seem to have died - ironically, there's more BM59 rifles and parts in America today than ever!
To answer your question, SAInc assembled a lot of 'E' rifles using standard 7.62/.308 Garand barrels, that appears to be the care here as your barrel has SAInc markings not the SAIU (Italian manufacturer) markings common on the 'E' parts kits.
How's that beast shoot?
Eli