I just had Toyota dealer check original specs with the VIN. Maybe this info will help someone else as well. According to dealer: before being sold for the first time, the truck went to a distributor called Gulf States Toyota here in TX. They installed what is called "Security System Plus" (brand name unknown but could be PERMAVIN). Even though a Toyota distributor installed the security system before the truck was first sold, it is classified as 'aftermarket'. They gave me another part number for key fob, different than what they first told me since they dug deeper. If I find one and it works I will post the part number for anyone with this system.