You will need to use an odometer Statement and it will need to indicate that there is a descrepancy. Make sure you let any potential buyer know this as they can come back against you and the dealership later and claim fraud otherwise.
I am not saying you need to shout it from the roof tops but I would make sure they sign the statement and that you go over this with them and let there be no misunderstanding that there is a descrepancy. I will save you from state investigators and attorney's later.
Hope that helps.
