Garand M1D rifles went to many different nations. In the US, all they care about are US issued and retained rifles. Most US collectors are hardly aware of this. 6167, I think it was you I bought a Garand M1D from. I don't remember. I had a hell of a time finding out where it came from. It has the receiver's serial number stamped into every piece of wood. All of the part numbers are correct for the M1D etc. It was the serial numbers stamped into all of the stock parts that threw a wrench into things. Turns out, that was a Norwegian practise. Does that make the M1D any less authentic? Not in my eyes. I don't have a problem with Danish M1D rifles either or French, Italian, Turkish, Vietnamese etc. They aren't any less authentic. They may even be more desirable, because there are fewer of them. Even Canada had M1Ds, until they sold them to the Danes.
It's the same with No4 Mk1 T rifles. They were issued in Norway, Finland, Denmark, Holland, France, South Africa, Israel, India, Pakistan, Turkey, Canada, Vietnam, Australia and even some on lend lease to Russia. It wouldn't surprise me if some of them saw active duty with axis forces as captures. Does that make them worth less? Not in my opinion.
As far as having everything CMP documented, I think the US has truly undermined the validity of their own collectables.