Russ 90, are you sure ?
Aren't they both 5 x 100mm ? I don't think there's any difference in the offset between the 15, 16 and 17" wheels for these cars. I know for certain that the PT 16" wheels will bolt up without clearance problems to the G and J body cars with the 5 lug hubs.
I have a PT GT with the 17" wheels as well as a Maserati TC and two J body LeBarons. To my knowledge the Q, J and G bodies have the same 5 lug hub setups. I've cross swapped wheels on these cars between the 16" PT chrome wheels on a 2002 PT but never with the 2005 GT with the 17" rims. Unless I'm mistaken, the bolt patterns are all the same. If it wasn't so cold right now I's pull a wheel off the PT and see if it would fit one of the LeBarons.