I have been wondering why no one has tried to replicate the mufflers on that set. I understand now you are cutting up 2k hoping you can get the sound right but would pay for it self quickly.
Same for the M-58 mufflers as I heard they sound good when the internal flaps still function.
So after some research found a guy had made a replica and from all I can gather they were hollow case mufflers. But that old thread had no pictures so I can’t confirm.