Like the collar disk of my great grandfather, I think AI is going to produce a lot of head scratchers for us

I don’t think the VC or NVA used the embroidery techniques that are used on this flag nor did they use western numbers.   Back when these flags came out there was little information to be had, I had to buy one to find out about it. 

Rest in Peace Larry.

I will miss you, Friend!

I have made some photographs of construction details of various North-Vietnamese flags that are on display at the 'Ho Chi Minh and Military Zone 5 Museum' in Da Nang last December. I have no reason to believe these are fake, but who knows? Anyway, maybe they are of assistance.                 This was actually a pretty decent museum with a good selection of items on display, although the story told is VERY one-sided. It is located on an active military installation but has an outdoor display area as well. When I was visiting I had the whole place to myself, no other visitors. I would recommend a visit if you're ever in that area.   I did see a few flags of the type the OP posted at the Dan Sinh Market in HCMC (Saigon) and I steered clear of them. I did get some good VC/NVA field gear there though 🙂    

Good catch, EE87! Eleven years ago and you still remembered it. Dang, that’s impressive … I can hardly remember what I had for dinner a few hours ago!

Is the engraving officially or privately done

Yes, you see them on occasion, but not a standard issue item. Below is a USN nightfighter pilot from VF(N)-90 aboard USS Enterprise in 1945 and a USMC PBJ pilot from VMB-611, also in 1945. 

I remember reading about this years ago. Same thing with the Corpsmen. Originally, they had matching sets. 2 crows, one on each sleeve, eagles facing front. But they were told to split the pairs and wear them on the left. That’s why you sometimes see Corpsmen crows vs on Marine uniforms, facing to the rear.   While I have seen Marine uniforms with only one chevron, they are pretty rare. Guys just went to shops off base and got the second one

This is the story of the Rose-Bailey wagon train. They encountered the Mojaves at Beales crossing in 1858. This triggered everything that followed. https://mojavedesert.net/mojave-indians/us-04.html