To the best of my knowledge there are no laws against restoration as long as
there is no intent to defraud. If your intent is to represent the actual
mileage, go for it. The worst that can happen is if some subsequent owner
opens the dash and notices that the sealing paint is broken.

Once you get the odometer out it is easy to set it to any number you like,
and much easier than trying to turn the speedo with a drill. Just be
careful when you take it out that you observe carefully how it was put
together so you get it put back together right.

I've had a couple go-rounds like this. In my 164 I broke a speedo cable
in Panama and it took me 6 months to get the right replacement. I added
an assumed mileage based on historical data to make up for the 6 missing
months. Currently the same car has the wrong speedo gear and is actually
accruing about 20% more miles than the odometer shows, and has been doing
so for the past 50,000 miles. One of these days (when I replace the cracked
dash and seized heater fan motor and get the right gear in the OD) I will
reset the odo to more accurately reflect the actual mileage. Should put it
close to 300K.

Don't sweat the small stuff. We know you are not going to sell this as
an "almost new" car!
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma