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)

Contact Younggun2.0. He has made some brackets and might be able to answer your questions. He might even post on here.

Why are you trusting aluminum seat brackets? Is this a street car? If you ever get rear ended hard those will rip apart.

Aluminum super stock brackets were for drag cars. Do you really think that NHRA would allow something in a car that would rip apart in a roll over, let alone a fender bender at a stop light. Aluminum is a lot stronger than you think.