My answer to the initial question is YES, YOU CAN AND YOU SHOULD install a 24 - 26" long x 6"dia. glass pack or flow trough muffler in place of the protective screen. It won’t affect performance and look but it definitely will reduce decibels! Protect your hearing, deuces are noisy enough! I prefer to listen to all (strange) noises, even some conversation and not just to a screaming open exhaust!
To install the deep water fording kit I had to convert my exhaust system to the vertical stack.
3" stainless pipe was routed under and trough the RH fender straight up without any muffler, following the old KIS principle: Keep It Simple! But after the first acceleration it became clear that the job wasn’t finished yet. The truck was simply way to loud, even for hard core deuce heads! So I built my own “glass pack” from stainless steel scrap metal. Instead of fiberglass I used rock-wool insulation material (higher melting point!) to stuff it.
Regarding noise reduction this homemade muffler works better than expected. The difference before/after was impressive! And it is compact enough so that it can’t be seen from the drivers position.
Drive safely (& healthy),keep you deuce quiet!
Gerhard