Nope, no Fido, didn't eat any Vietnamese food, while there, nor any since. I did eat some stuff in Bangkok, while on R&R, that was likely some unidentifiable four-legged or crawly thing. Enough Singhi beers and you'd probably eat anything.
It was 50-years ago, but this is how I remember it:
The 101st Airborne and their 105s were stationed on one side of the base, Phan Rang Air Base, and the Koreans (ROKs) were on the other side.
One of my shop's senior NCO, a guy named Shipwash (honest, that was his name), spent much of his time scrounging, and discovered that the 101st troops had never been served hotdogs, which was an Air Force mainstay. In true scrounger fashion, Shipwash purloined a supply of Air Force hotdogs and traded them to the Army for similarly purloined steaks. Subsequently, our shop had a barbeque and foam (thank you, Joe Ely). That was the only time in the entire year that I ate steak. Oh, we were served "mystery meat", but it wasn't steak.