Fusor is designed to replace factory panel bonding when repairing/replacing body panels on newer unibody vehicles. Many OEM's (such as Toyota) do not approve of panel bonding when repair their vehicles.
I would not recommend it's use on any First Gen Firebird panel. I have a local collision center that I talked to about removing/replacing full quarters on my '69 hardtop and they were going to panel bond the lower front edges at the rocker panel. I do not agree with this repair and will not have them do it. I will probably do the repair myself (someday).
Anyway - be careful how you use this product. It is designed for a specific type of repair and I have done consulting at collision centers that had technicians that thought this product would replace welding in most cases.