Well the good news is that there is only one code for your 98 SVT. It's RJL1. It's possible they flashed it with a normal run of the mill contour program that was designed for 87 octane. The dealer should have written on the front support what the new calibration is and the date. I believe it's required. The bad news is that the only way I could tell is if you sent me the ECU to read and compare it with the correct calibration. If it is wrong then you need to have the dealer reflash it. Both the SVT and the SE use the same strategy so it would run on either one and a scanner won't help you tell them apart.
You other option is to order a chip for it but that is the more expensive route and I'm sure not your favorite. The benefit is at least you will know it's the correct code and you'd get some gains out of it.HTH
