There is quite a market for bolts, trigger groups and op rods on e-bay.  The bolts are going quite high according to some of the guys on this site (like $150+ consistently for TRW bolts in a range of conditions)

What I'm wondering is, if there's a chance you/I might buy a USGI bolt that has had the original USGI extractor/firing pin, etc replaced with junk parts?

Well, I guess I know there's a chance, but does anyone know how often this happens?  And how could you tell, once you got the bolt that it had, if, for example the seller guaranteed you that it was ALL USGI?

I bring this up because of some recent reports of fake collectibles being traded on e-bay.  I know how to tell USGI bolt based on the proof mark, but how can you tell about the other parts?

Send me an e-mail and I can send you the specifications for the M14 coil springs.  [email protected]  That will help some with the ejector and extractor springs.  If the firing pin is Parkerized it could be commercial made or the first USGI version.  Also, Chinese firing pins are chrome plated but they are okay.  Does the stem of the extractor extend below the bottom surface of the bolt?  If so, you should replace it.