Jamie -- I tried to find how to tell if it has ,5 or 6 speed and could not find anything. Probably can only tell be the window sticker. There is no code in the VIN for transmission. And without having access to a unit with 6 speed I don't know how the shifter might be labeled.
Maybe someone e out there with a 6 speed can tell us how the shift is labeled. If I get that info I'll add it to the manual. I did put a revision in for how to read the VIN and tell if you have a 350 or 450 chassis.
Ed & Bev Felker
Retired USAF Col and retired Nurse
Traveling with Lily & Bella ('Teddy Bear' breed)
2015 Vegas 24.1 (E-350)