I suppose the spot welds could be drilled out, but that is a big job. Also, the rear cab panel to floor joint is rolled making disassembly much more difficult. The beltline sections are soldered together so you will need to address that joint as well.
I would seriously look at your dent and attempt to massage the panel back into its original contour.
I think the panel in question is the same from 1939-early 47. I happen to have a buddy bringing over his 39 today. I will try to remember to compare some measurements with my 41.
