Unless the bushings have been replaced at some point, the brackets will be spot welded together. Usually 4 sort of rectangular looking welds. It is possible to use a spot weld cutter and cut around the welds to separate the two halves with less damage. There is no real reason to weld them back together, although it would make it a little easier to get the bar attached to the vehicle again. Otherwise, once it's bolted in, it isn't going anywhere.
The brackets aren't available anywhere it appears. Last I saw was about 15 years ago when I bought a bushing kit for my car. It was the 2 pieces of the bracket, the bushing itself, a friction plate and the fasteners. If memory serves, it came from the dealer but now has long since been discontinued
