Gil, it was pretty sympathetic deact work. Very little weld to be honest. The receiver and chamber was drilled through and a hardened pin welded in and the barrel had been slotted under the handguards. The gas piston had been shortened slightly and the bolt face ground at an angle as usual. All parts working apart from the obvious. Later examples I've seen were much more heavily butchered with no piston or even gas tube, etc and as you say full of weld.
Cheers, Kev