Pratt & Whitney
did run pilot's courses in years gone by (did mine at the Papuan Hotel in POM in 1982).
Whilst BGT is no longer a requirement, it is very useful to have some knowledge of why things are done a certain way, and there are differences between PT-6's and Garrets or Allisons.
Although I doubt that he runs pilot courses, "Mr PT6"
MR PT6 MAINTAINENCE AND REPAIR SPECIALISTS - BRISBANE AUSTRALIA has an encyclopaedic knowledge of this engine, as does Ray Williams at P & W.