Hi David, there are plans to do a Vietnam version of Hind & Seek as it's a similar MO – asymmetrical warfare.
The basic rules will work for Vietnam, but I will probably go into more detail about jungle terrain as that's more the defining terrain of the Vietnam war – whereas mountains and the relation between high and low ground are one of the defining features of terrain for the Soviet-Afghan war.
To fully re-skin Hind & Seek for Vietnam I would need to re-write the Assets to be a more Vietnam flavor and stat out the forces and weapons involved. I would also write some more scenarios and mostly write the system from the ground up, just using Hind & Seek as a template.
I would also need to come up with a snappy name… "Something & Something" Ideally with a huey pun or somesuch…
Unfortunately the Vietnam version would be a wee way away, as I'm gearing up to write a modern air combat game next (which will cover the Korean war and Vietnam, up to 2000s tech), so I will be working on that first.
If you do end up buying the Hind & Seek rules, I could draft up some Vietnam forces for you so you can at least try things out and see how it plays. The assets will likely still work fine as they are, they just wont have as much flavor in the text.
My email is in the Hind & Seek rules in the notes from the designer section, so feel free to drop me an email if you end up buying them, I'd be happy to help you get them set up for 'Nam.