Do you have any pix that show the differences in those chevy pans and what you had to do to get them to fit?
Hi, that would be me! My labor bills on the rust repair were pretty heavy even with me helping. My car had been "repaired" badly in 1992 according to paperwork I got with it. There was a patch panel on the driver side and then they covered the whole floor pan and trunk pan with bondo and some kind of thick POR type paint.
I had to replace inner/outer rockers both sides and the front floor pans both sides. Rears were like new, oddly. Trunk floor was fine, it was the rear most part of it that was wrecked, full of bondo and the body brace that runs across that back had rotted away.
Don't fall into the trap of Pontiac=Chevy for 49-52. The only exception is the Canadian built Pontiac's that use a Chevy frame and body with different front clip. I didn't know this at the time, and as a result my front pans required a lot of brake bending, and minimal cutting to get them to work. They dont have the large 'sunk' spots in them for the body bolts, so we'll have to work around that. My floor pan braces were in tough shape, but I found no NOS or other ones that would work, so we rebuilt mine.
I got my rocker panels from the rocker king, and took a set that had the holes for the stainless trim already stamped in them. The rear most part of them that makes the bottom of the rear fender "pontoon" was tough, we had to work those over, and re-hang both rear doors on the body to get the lines nailed.
I did see a set shown on Ebay that were for 49-52 Pontiac, claimed as NOS front pans, but they looked nothing like the front floor in my car, so I didn't get them. Was around $600 for all my parts. I had not realized how bad of shape my car was in until we got it blasted and on the body roller.