odometer question for new gauge cluster

Is the truck mileage exempt? In some states, once a vehicle reaches a certain age, it can be registered as mileage exempt, which makes the actual mileage unimportant. I've done this with my Mach since its had the cluster switched at least once, and I did drive it for a quite a while without a working speedo/odometer. I think if you've rebuilt it, it might be ok to make the new odometer read 0, but only if the truck is registered as mileage exempt.
 
how do i check if exempt? Is that something done when registering b/c the truck isnt registered at the moment. I'm gonna go change the tags over to it from my '66 and register it as soon as I get it running and painted.

actually another good question is how to roll it back..its on 2700 miles and it'd take a looong time to get to 00000