Any good company will transfer the VIN, also. If you do/did it yourself, then the VIN is included in the file transfer.
It's not a must, but if it is checked and the stored VIN doesn't match your car, it could throw up some red flags. If you had someone else do it and you just told them what mileage you want it set to and you are even a mile off, it will not match the mileage stored on other units (conflicting info on whether the mileage is stored elsewhere vs operating hours, but it surely is)...more red flags and possibly worse. Misrepresentation of vehicle mileage is a felony. If they didn't ask for the old and new cluster to transfer your files, then they did it wrong.
If it were me, I'd just copy and transfer the entire file. This is standard procedure for the DIY.