Will there be damage if torsion bar keys are tightened?

When you tighten the torsion bar you will cause the spring rate to change on the front suspension which means it will bounce a bit more, in theory. Also you will cause the top of you tire to tilt out since the upper and lower a arms are not exactly equal, so you may need a front end alignment too. I've adjusted both a 1992 and 2001 3/4 ton and never had any issue. Cheapest way to level the front end up.