i don't think any dealership is going to be too happy to fix it... you can try, but i don't think it's calibration i think it's just how they go on... the tach should point directly down when it's disconnected and you've pushed it around toward 8k rpm, and then let it fall to the 6oclock position.
don't put them on according to where zero is, put them on according to where the spring/whatever mechanism it is behind it thinks it's pointing... easiest way to do this is to wind them all the way around so they rest pointed full down and make sure they're pointing straight down.
I HAVEN"T TRIED THIS AND IT MIGHT NOT WORK, SO ALL DISCLAIMERS APPLY.
but get back to us if you figure out how to fix it.
the speedo's probably the same(rests full down once you wind it around past 140) but i have no idea... you can play around with it(how much worse can you make it?) but i don't know any easy fix for this.
i yanked on them pretty hard doing it, they were in REAL good- maybe yours weren't on tightly to begin with... but that's weird.