Good question. I took mine off the bike and removed both bolts holding the baffle in and tried to pound out with baby sledge hammer and broomstick handle and they would not budge. Bought set of Bassani Pro Streets instead and love them.
Welding the baffles might be new. I bought a set of SEII slip-ons in 04' and the baffles are not welded. I did need to remove them from the head pipes, coat the edges with WD-40 and then gently hammer out using some round stock and a small mallet.
Last year I put a set of the SEII Pro slip on's on my Dyna and love the sound. They are definitely have a lower rumble than the regular SE slip ons. I was told my quite a few that leaving the baffles in on the SEII pro is a good idea to maintain proper back pressure for the lower powerband. ALso when I stomp on the throttle these things bark pretty loud and still dont have that tinny sound like some others.
I plan on putting the baffles back in after i drill them. it has been discussed on here before , that drilling out ALL of the outside holes around the baffle from 1/4 " to 5/16+..
or something like that , will give them a deeper tone yet.
ive also thought about taking the baffles out, and replacing them with big city thunders, in the head pipes.