Learning, question on body lines

[JPM31]

Yes, I've used the search tool, but just want to see if I'm on the right track.

Been looking at trucks, and reading up on body lines/alignment with cab bushings, spacers, etc.

This is a Texas born truck, so rust is at a minimum, but as you can see form the pics, it appears to me that the drivers corner of the cab sits way low compared to the bed. The passenger side appears to be good, and the bed appears to be level (notice the downward slope with the rear picture)

I assume, and again just based off of photos, that this would likely be a worn out cab bushing, or potentially a rotted cab mount on that side?

When I read the forum, guys are talking about, 1/8, 1/4, 1/2 inch gaps....this looks like a good 1-1 1/2 inches.

Thanks for any input