2003 vs 2002 Tundra Keyless Entry

My son just bought a used 2002 Tundra with the SR5 package. I thought all SR5 's came with keyless entry but not necessarily an alarm. When we picked up the truck, the dealer only handed us one key and no fobs. He claimed that's all he had. He said I'd have to drop off the truck to see if it had keyless entry. I've looked thru the forums and looked in his truck but I can't find the beeper under the hood, so I'm assuming he doesn't have keyless. I have an aftermarket alarm installed in my truck with the keyless entry included. It's wired in parallel with the OEM keyless as my fobs still open the doors. Does anyone know if I can just take the OEM keyless from my truck and install it into his? I've looked thru the wiring diagrams and can't see any major differences in the wiring. Any help is appreciated.
Regards,
Dave