Bit complex but the book or authorised TO&E for US infantry at the time was a 10 man squad.
Squad leader and then two teams (nominally Alpha and Bravo) each with a fireteam leader, a grenadier and riflemen, all with the M16 save for the grenadier with an M79. In theory one of the riflemen in each team was designated an 'automatic rifleman' but he had the same M16 as everyone else.
The M60s were not squad weapons, although they were sometimes attached. On paper, apart from the three rifle squads, there was an 11 man weapons squad. Squad leader, 2X M-60 machine gunners, 2 X assistant gunners, 2 X M67 RCL gunners*, 2 assistant RCL gunners and a couple of ammo bearers, making up the numbers for each team. In theory the assistant gunners and ammo bearers were pistol armed but could and would often be armed with M16s.
Now that's the paper org. In reality, with reduced numbers, through illness, casualties, leave, people being posted on courses etc, the average US squad was around the 7-8 mark in terms of manning and sometimes lower. The M67 RCLs were rarely carried on operations due to their weight and often the M60s were attached directly to squads rather than a separate weapons squad. Sometimes the weapons squad was retained as a purely machine gun squad with everyone but the two gunners as essentially ammo bearers for the guns.
With a pinch of salt, the following site will give some of the possible variations to the paper org.
https://www.battleorder.org/us-army-vietnam-1970#:~:text=The%20Rifle%20Squads%20were%20divided,of%20the%20M203%20grenade%20launcher.
Worth noting that the while the M203 did see service in Vietnam it wasn't widespread outside of special forces units AFAIK, the grenadier remains armed with the M79 in most cases.
In broad terms, the rifle squads in Air Cavalry were initially 10 man squads, with a Squad Leader, two team leaders, two grenadiers and five riflemen. Four such squads to the platoon. Late in the war a man was dropped from the squad but an M60 authorised for the squad seeing a large increase in firepower.
The USMC is an entirely different organisation, with three fire teams and 14 men, including a single grenadier on paper. Let me know if that's what you are after.
* In airborne platoons this was in theory an M20 Super-Bazooka but it's a moot point they were rarely carried.