Sorry, not my experience.
I carried an M-79, and an M-16A1. And at about the time they took our M-79s, they gave us M-16A2 with the M-203.
And FYI, I also had an M1911 in addition to the other weapons. that our team had (like the M-60).
Myself, I could not imagine a grenadier being sent out with an M-79 and no other personal weapon. Sounds like suicide to me.
And FYI, Like Chuz Life, USMC. 0311 from 1983-1993. Held every position in a Marine Rifle Squad. Even back before the M-249 SAW, when the "Automatic Rifleman" just had double the ammunition of a regular Rifleman. Even trained in the M-202 FLASH and the Bangalore Torpedo.
Try explaining those systems to anybody that had never seen or heard of them before.