hmmm....are there any baffles inside or is it perforated tubing w/ filler on the sides? I would probably get that welded shut after you decide to keep it, as the JB weld may accumulate leaks down the line.
Food for thought, my dirtbike has a muffler that requires packing every so often. And it's dyno proven hp when packed over being empty....but then again,
we're just in it for the sound