Quoted:
never happened.

Quoted:
Jmishusmc

You are making the assumption that during the War,
that the NVA marked captured M16-A1 upper receivers.

Where's the historical evidence that they did so?

Having been to many military museums in VietNam,
I can't recall seeing any captured American weapons
that had been marked by the PAVN.

The one exception would be those American
weapons that you could shoot in Cu Chi, at their
live fire range. Some did have, IIRC, paint or some
such rack markings.

Any photographic evidence that you have, would be
most helpful.
It’s been discussed on arfcom before. It seems there were two variations of the marking. One is a simple 5 pointed star and the other is the same star but stamped into the upper in a way that it looks like a star within a star. Both are on the left side of the upper somewhat diagonal back from the forward portion of the carry handle.

Quoted:
https://www.ar15.com/forums/AR-15/BFPU-XM-with-my-spare-parts/123-744953/


Check out the left side of the upper on my build.  I discovered the communist star stamped into it after removing some thick paint.

Quoted:

All of your pictures are dead now in that old thread.

Quoted:
I thought it was gone forever.  The star is where the front of the handle meets the body of the upper.  You can see it well if you enlarge it on a cell phone.  How did you get the picture to come up?

Quoted:
Sorry; I guess my snark didn't translate well. Because Imgur recycles image URLs, that's what it currently shows in place of whatever image M4it had originally uploaded.

I'm not seeing your picture; I'm seeing an Indian lady dressed in some kind of traditional garment.