2002 era, shouldn't have to be flashed to work. The security, if it is equipped with one, will require the dealer to program the code, along with the VIN, unless a good, professional (meaning fairly expensive) scan tool is used (I'm talking about a Snap On, OTC, MAC, Matco, Launch- types the average Joe does not have). Ideally, given that era, someone with a working DRB-III, would be perfect. Here's the thing, if the truck does not have a security system, then after install, the truck will run fine, and will be able to be driven. The only programming that will be needed, is the VIN, PCM mileage, and possibly tire size - though that may be stored in the ABS module on that vehicle (it's hard for me to remember these things, and many other things, for good reason; but I'm not getting into it here). A dealer will be able to run the VIN, and tell whether or not the truck has a security system, another good way is to look at the key. If it has a grey rubber overmold, it most likely is equipped with the SKIM/SKIS system. If the key is black, chances are high, it is not.
