Pat, the FAM is your friend here. Look at Section 1, Sheet 1.07 for cab dimensions. The front cab mount holes are symmetrical side to side at 23.5 inches from centerline. Also see Section 2, sheet 2.00 for frame dimensions, that indicate the same distance from centerline for the corresponding frame holes. It also indicates the frame holes should be within 1/16" of each other fore and aft.
I think if necessary to center the cab on the frame, widening the passenger side hole would be OK.
