68' Super Stock seat brackets inquiry

I bought a set of aluminum 1968 Super Stock seat brackets off of eBaY for my 1968 Hemi Dodge Dart (clone) that I am building. I received them in the mail today.

I placed the brackets against the bottom of the seats, and observed that the top of the brackets are not the full length to reach the original holes inside of the seat front to back.

Was there a flat bracket? Or did I receive the wrong brackets?

Thanks

(I can post pictures if needed)