Even in '68 when I got there I saw M14s and M1 Carbines at Cu Chi. Yes, by then the M16s were the norm but a number of the camp guards used them as they had better punch at longer range. I also saw the pump shotguns with the 1903 era, 18" long bayonets on them too. While my tank's TO&E included grease guns, we had M16s instead and like many other TCs, I cut an M2 50 ground mount down to a pintle mount and had it welded on top of my cupola of my M48 instead of mounting it sideways inside it.
We later put a shield on the front as well and we gave the loader an M60 mount in front and to the rear of his Loader's hatch. Someone had an idea so we also welded standoffs next to the light guards in front so we could deploy a chain-link fence frame across the front of the tank with 'wing's that folded out on the sides to catch any B40s before they impacted when we dug in defensively.
By then we were mounting all sorts of stuff everywhere. The POL convoy trucks we escorted had some sort of small mines attached in a row on each side of the bed so if they got rushed they could blow a side and 'clean out' the brush. We also had a M42 'Duster' that would go on the POL runs with us too and that was just plain cool when those twin 40mms would go to work on Charles!!!! It it went 'bang' it seemed like we had one or two.