don't know if you'd call it an option, especially from the dealer, but it was possible to special order them from the factory - I had a 57 panel ordered for use as an ambulance that they put windows in, documented by a restopak for the vin#
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics