Hopefully someone has some suggestions for you. If the '67 panels won't fit, could a good upholstery shop modify the '68 Custom interior parts you already purchased to work and still look good? I searched various sources and found no other record of that on another '68. There's a thread on here dealing with "Firebird Mysteries". There are a lot of curious build differences in the 1st Gens, many that have yet to be explained.
The Body by Fisher tag on the firewall will have a code showing the build week of your '68. Might be interesting to know.
