I thought the A body was the bottom of the food chain, and only cane with a rubber mat? Try a fabric store, they sell lots of products. i got a nice looking carpet mat thin for my Camaro years ago. Looked plush, didnt add any weight to the car.
Spatter paint is a Chevy thing, same as a black engine compartment. Mopar uses factory body colour. I have a compressor, a pair of spray guns and i shot my own trunk engine bay inside and out as well as rear wheel wells.
Most likely be a philips head screw 1/2" long max. If the existing hole is there, take a piece of steel tie wire shove up the hole till it bottoms out. you now know how long the screws can be.