Bed Alignment

[Dashman]

I had the bed raised on my Dad's '72 to straighten the rear frame rails from a bad bumper strike many years ago. Before I raised it, it was crooked more to the left. First, I inserted the middle bolts, then I inserted the two front bolts.
One rear bolt is spot on, and the other is very near. Now that I lowered it and inserted bolts to secure, I have it nearly corrected.

Left Side Alignment:
Right Side Alignment:
Front Right Side Hole:
Front Left Side Hole:

I was about to ream the holes when I read someone's post here that the cab mounts can affect the bed alignment.

Front Left Cab Mount:

Is it possible to shift the cab over to the right, so that the bed will align without having to ream out the holes? Is there about 1/4" lateral play in the cab mounts? I'll have to install new radiator supports at the same time, correct? ...and shim the radiator supports so the fenders align with the doors? Do I need to loosen everything, or just the radiator mounts? Thank you!

*Edit: I measured the cab to frame, Left side: 17-1/4". Right Side: 16-3/4"