Those clips are to be used as "shims" in order to compensate for wear on the knuckle where the ears of the brake pads ride. If you have little or no wear don't use them.
You will never be able to match those contours with a piece of flat sheet metal, moreover, the contours provide structural rigidity. Buy an outer floor pan, trim it to overlap into solid metal then attach it however you wish.
I suggested an outer floor pan, which can likely be had for under $100, because of the bends and contours. It will save you the time and frustration of bending and pounding a piece of flat sheet into shape.
If I were going to keep the truck for an extended period of time I would cut out the bad, buy an outer floor pan and use what I needed of that to repair it.
I got the motor on ebay, the original I took out had yellow plastic tabs on the back. The new one had white tabs and had a "C1" marking which I believe designates it as suitable for a temp or fuel gauge.
Up until 2003 GM used Air Core gauge motors which are fluid dampened, over the years the fluid is lost. You can replace the fluid or the motor, I replaced the motor on my 99 K2500 Suburban.HERE is a link with quite a bit of info.
It looks to be in original condition other than the paint, which was done by the PO.
I got it at a local auction about 5 years ago, it came with a pipe wrench and an adjustable wrench.
Built mine last June.
30x40x12 (height is actually 12'6)
Bought the kit from a local Mennonite company and had a carpenter friend help me erect it. $13,700
Prepared the site myself using my brothers equipment.
Gravel $500
Concrete is 5 inch thick fiber reinforced 5000psi plus rebar.
I have a...