The bracket on the left is an 80s reproduction toolbox strap that was welded onto a 47 frame. It is probably .25 wider than the original strap on the right.
Whoever welded the toolbox strap on welded it at every available section that the strap was touching the tube. Original toolbox straps were only welded on the outside edge. Here you can see where I cut into the strap to remove the funky repro bracket. I left as much weld on the frame as possible because it is easier to see when you've cut through the bracket as opposed to cutting through the weld.
I used a cutoff wheel to rough grind the weld off of the tube.
I filed the rest of the weld off, and sanded it with a roll loc 3M disc.