I agree completely with Mark and Ed.
I've purchased a filter and the oil specified in the manual and have changed it to what is approved in the manual. The lesson learned about the dealer may not be that expensive in that it taught me to ask specific questions before having work done. It seems to me that if a dealer intends to do something different than what is specified in the manual, it should be explained to the customer prior to performing the work. That way the customer may make the decision to allow it or ask for documentation on the alternate choice. In this case, though I have searched the different owner's manuals for each year of the camhead engine in the RT, I can find no reference to 20W-50 being an approved oil for that motor.