I am no expert, especially on 80's Avanti's, but it appears someone cut away part of the firewall where the (later model probably GM adjustable) steering column goes through, then closed up the hole by adding some sort of plate on the inside of the firewall (possibly part of the more modern column). Is the area inside the firewall around the shaft solid to the touch? Wouldn't surprise me if that was done by the Avanti II factory back in '80. Hopefully someone with an '80 can look at their car to see if theirs looks like that (I once had an '80 but sold it about 10 years ago).
Wouldn't be too difficult to fashion a plate to cover the "hole" in the fiberglass if it bothers you.
The parts manual for the original 63/64 Avanti's calls for a seal 1350435 and a gasket 1350434 in that area. Studebakerparts.com carries both at $4 each, but neither would cover that large opening. You might try contactng Nostalgic Motor Cars to see if they have any further information.
