Exactly that one. And even a team of SF has to maintain longer range comms with the team house, or even the AOB (Battalion level, usually not co-located) The body wire doesn’t necessarily give longer range - I had trouble in Iraq reaching about twenty klicks, and over very flat terrain in the Jazeera desert. For longer ranges I believe we used the PSC-5 with the SATCOM antenna. Not really my purview though. If it didn’t have a trigger or a detonator on it then it wasn’t really in my wheelhouse.
Ah, and for a sling on the M4 I do know that three point sling was very popular then. I made them for the whole team from components I bought at REI. Single points were also somewhat popular. It seems the basic two point sling wasn’t “cool” enough back then. Of course everything is cyclic. The two point with a quick release lengthener is now the shiznit.