It does help Tom, Thank you!
I'm just trying to learn generalities about them some more as they do peak our interest.
As far as I can tell, 3 layouts all years - thank you
Dual vs single axle
- only real difference is headroom (and axle
Some have fiberglass bottoms that cover frame and tanks - some dont
Later years (1990+) had reinforced roof to handle a/c.
I think that's about it. Curious on production numbers too but probably hard to know!