"CampyBob do you know of a source for the ak-100 rear trunnion?"
they can be had with the krink (steel triangle style) folder available from k-var. every so often, the plastic left-side folder and hardware will turn up on ebay (ekie just bought one, plum coloreded, for $90 on the subguns board.).
"Hey Campy, there is this big fuss over AK-103/101 autheticity due to "rivets and dimples". What exactly makes an AK-103 from Izmash authentic that the Saiga rifle or AK-USA or Krebs conversions don't provide? The Saiga is basically an AK-100 series after all..."
not exactly. the magwell guide dimples are missing from the saiga and the rear of the receiver is not profiled at 7°, nor is it machined for the folder pushbutton or locking latch. the saiga is closer to an akm than the 100 series.
"If you change a SAR-2 to a Bulgarian version of the AK-74 using Bulgarian parts the trunion has to be changed because the Romanian and Bulgarian barrels are different diameters."
mike is correct, the journal diameters are different. also, the bulgarian rifles use the wide lug bolt and trunnion...the romanian ak-74 uses the narrow akm style locking lugs.