Yeah that's the problem. Switching frames will require the gun to be retimed anyway, so you're not doing anything wrong by adjusting the timing rod.
You will also need to switch some hoses around on the frontblock. They are currently setup for a slide frame, hinge frame will require the front and back hoses on the 3way to be swapped around. Obliviously leave the LPR/middle hose on the 3way alone.
It sounds like whomever you were talking to about cockers really had no idea what they were talking about. If you need any help getting the gun timed, we will be here for ya.