I will check with the dealer, but just looking here first. This place knows more that what most dealers do.
Are you saying that the on/off and the set/resume/accel switches are one unit, or the complete wheel? Even if it is both switches, would be better than a new wheel.
Last time I replaced them, you had to buy both buttons. If yours has ON/OFF on the left and SET ACCEL /RESUME /COAST on the other, it comes in an assembly with wires and connectors that connect under the horn pad. I paid around $75 for the parts and did the work myself. It was on a similar vintage truck to yours,