1966 plymouth valiant 4 door carpet hold down plates

I saw that but I am not paying $37.42 to ship it. That is way too high. I have contacted him. I wonder where he got that part # from.
can't blame you there. There are other options that require a little fab. You can buy the aftermarket blanks if you don't care about perfect originality and cut them down to fit. So you will start out with an A body blank and then ban saw down to the size and shape you want and drill the holes based upon your original pieces. You will end up with 3 pieces per side that look like new but not exactly original. Not ideal I know but some things will just never be reproduced. It looks like a new old stock piece.