They are similar, but are indeed different.

The firebird rear seats will fit the Coupe and the Vert, but I believe the Camaro were fifferent from coupe to convertible... so for a Camaro you had to get a vert seat for a vert, and or the vert seat would be too short for the coupe etc...

But the patern for the standard is very similar.. but it is different. (especially in 67/68)

Brett - 67 Drop Top 455!