So the 174th Sharks went to Vietnam in 1966. They only had UH-1Cs in guship platoon. Sinc ethey came over in 66, it is still POSSIBLE one could have been armed with the M16 quad M60C/M157 rocket pod system, however, all the early photos I ahve seen show the M3 24shot rocket pods or M5 40mm/M157 armed “Frog” gunships. You can easily make a Frog ship though by leaving off the quad 60’s. I think tha’s what I would do if I were you. Have a Merry Christmas and good luck!
Ray