Oh if its a 2.5 L you shouldn't have to have the dealer flash it, since about 90% of the 4 cyl don't have anti-theft. To get your part numbers your gonna have to remove the pcm. On the passenger side firewall. Unbolt the wiring connector (10mm) and then unbolt the two bolts holding the computer in (10mm). Then you can slide it out. The big 4 digit number is your flash version (there should also be a sticker with the same number on the passenger side fender in the engine bay). When I say number its letters and numbers. FOr the PCM model it will say EEC-V, then I think on the next line it will say something like MP2-yada yada. That line you should match up. If you match up the model and the flash, and you have a 2.5L you should be able to just swap it out. If you don't have a 2.5 your gonna need to get that thing flashed because the anti-theft module (which comes in pretty much every ranger without a 4 cyl, for that year) and the pcm are pair to each other. So when you add a PCM that isn't paired its not gonna like that. Also for Ford to flash it (check if other people will flash, there is a guy here in knoxville that does a darn good job for 60 bucks!), they will need two keys. This is so that they can bypass security to reprogram the computer. When you do something along the lines of put one key in and turn the ignition on and off a few times and put the other one in and do the same thing this disables the security.
Quality Engineer (Electronics) for Kia Motors
University of Tennessee Electrical Engineering Graduate
2000 XLT 2.5L A/T