When the title is transferred, the seller is required to state, under penalty of perjury, that the odometer is accurate. If you suspect the previous owner would go to such extreme lengths in order to hide the true mileage of the bike, then you should run away from that seller.
To answer you question, it is not at all straight-forward to disconnect the odometer on the WRR. Its input is electronic and comes from the drive axle, and the meter is part of the ECU so it cannot be easily disabled.