Reader's digest version: Keep looking.
Glutton for punishment version:
The good news - the '97 cab bolts right up to the '00 frame!
If it is supercab, skip next section:
The not so good news - as the '00 cab was 3.5" longer, this leaves a gap between the cab and box. As chvlfrk said, you can separate the rear frame and shorten truck to remove the gap. Note: rear driveshaft also needs to be shortened by the same 3.5".
Alternatively, you could get cute and just put in a spacer, and no one would be wiser.
Resume for all cabs:
The bad news - the '00 has PATS, so without the dash from your rolled cab and then mixing the '97 wiring for lighting/etc with the '00 wiring for engine, the truck won't start/lights won't work. The silver lining is: The '00 dash will bolt right in in place of the '97 dash, so it is just a wiring exercise. However, without EV&T manuals for both '97 and '00, it would be a challenge.