Is there a difference in the FSB of a RPKS-74 and a AK-74M?  I'm looking for a FSB without the dimples and having a heck of a time.  FRom teh pictures it doesn't look like it has bayo lug but i could be wrong another thing there seems to be a different bulge at the front of it for what i dont know.  Thsi guy has a parts kit with one of them in it and i was just wondering if they were interchangeable.

http://www.gunbroker.com/Auction/ViewItem.asp?Item=37935977

Bayo lug, and it only has one dimple versus 2 ..

The newer version of The FSB as no dimples right?  Like what they would put on a 100 series gun?  So the new RPK-74 have one dimple insted of none at all?

Quoted: The newer version of The FSB as no dimples right?  Like what they would put on a 100 series gun?  So the new RPK-74 have one dimple insted of none at all?

Actually it depends.

All Russian military guns have the dimples. The barrel parts are basically welded onto the barrel. Thats what the dimples are from. Export rifles (like the AK-101s for Indonesia, as well as the Saigas sold in military configuration in Europe) may or may not have them, as the parts might be pinned on instead.