It is mismatched., the welds may have penetrated the trunnions deep enough to be an issue. Not really a good parts kit IMHO.That's been on GB for a looooong time (wonder why!). They are pretty horrible rivets though, the only thing about that gun is its original barrel, scrap the receiver and still have a good parts kit.
Depends on your definition of "safe". Those welds look like shit. As a parts kit, maybe, as a shooter. I'd have to say, no.holy shit man, I have never seen rivets like these!
Side Folding Bulgarian AK74 5.45x39 AK-74 ak47 : Semi Auto Rifles at GunBroker.com
is this shit safe??