The bench was/is a fairly rare opt. Out of curiosity, is your 'bird an auto or manual trans? If manual, is it a column or floor shift?

Paddock has the deluxe covers for '68-9, the only way you could get a bench. Seat back foam is the same as bucket seats, but the bottom may have to be fabbed.

I bought a '67 standard bench for my cammer since it's a column shift. It's nice to have that arm rest, and extra seat space in case you need to pile the crew in.