I've seen some faked Pre 64's where the gunsmith's buddy would do a photoetch of the original stamping and redo the markings on the rifle after gunsmithing and/or modifications were completed and before blue. You would have to be very good and have a good scope to detect it had been faked- but I was shown how to detect this type of fakery.
I will say this gunsmith never tried to pass these off as original pieces- his aim was to make a clone as close to original as possible for his own uses. Not even sure he ever sold any of them.
This is one of the reasons I don't collect Pre 64's, even though I own several of them. Shooter grade for me, as I want something I can hunt with and not cry if it gets scratched, wet, or a bit of rust on the metal....
Bob
