GOOD POINT there Boeing727! IMO, having used several, I tend to believe the short "Tongue Muffler" is simply an Exhaust Director. The long ones may
provide some noise reduction but not much. They do provide enough back pressure to provide some tank pressure if so desired.
Many flying facilities do require a "muffler". The tongue fills that requirement I suppose. It also looks better than a big muffler hanging on the machine, especially certain models that are rather less pretty when a big muffler is hanging out. This being CL, I guess you are doing it on CL models. Should be fine there and less weight up front, plus looking much better.

I still like that "politically correct". Also the name, "Boeing727". Almost 2/3 of my time during my 28 years airline was spent in that machine. Warmed all 3 seats as time went by. [8D]