I have flown the A (only one was produced), B,C,D and E (military version, actually was originally the C) all on the same type rating. We did have to do a short (maybe three hours) difference course from the C to the D. Flight Safety in LGA had a C sim years ago but I don't know if they still have it. Ask the Gulfstream guys over on Flightinfo.com where they train. I think they still fly the Beech. Have fun. It is a good, strong and safe airplane.
Jet