Since there are many different rotisseries out there, the answer is determined by answering two questions:
1. If the physical connection does not interfere with the glass, then you pass gate #1. Most that I've seen and used attach to where the bumpers bolt to, so no interference. Also, since bumpers are the same for coupe/vert/2+2 the fastback is not a factor here.
2. What is the weight carrying capability of the rotisserie you plan to use, and what is the weight of your vehicle (considering what is installed, and the glass adds weight, and the fastback perhaps a bit more glass weight).
More than likely you will be ok.
The other consideration is how structurally sound the car is. If there is copious rust, you might want to consider bracing where you remove the doors to eliminate sag. If you are not removing the doors, see item #2 above.