In regards to US characters for a Vietnam setting, there's a good list of suitable basic equipment that was done for The Morrow Project RPG.
The main page for the site I'm sourcing these from can be found here: -
http://www.thesupplybunker.net/morrow.htm
Note: A lot of the information on the site is done up as either plain text docs or pdfs.
The specific ones for a Vietnam setting are as follows but you might have to check when some things became available as they weren't issued until late -70s e.g. the PRC-68 radio: -
1970s-80s US basic webbing list
http://www.thesupplybunker.net/pdf/s...975_-_1988.pdf
1970s-80s era US military radios
http://www.thesupplybunker.net/Morrow/radio.txt