Then I guess you wouldn't really need to worry about the VIN matching.
Considering the year difference, 98-99. Sometimes sensors on the engine change from year to year. Here is your homework for today... compare the part #'* of these sensors at www.rockauto.com
between 98 and 99. If your 98 engine has a sensor that is not compatible with the 99 PCM, then it might cause an issue....
Throttle Position Sensor-TPS
Inlet Aircontrol Valve -IAC
Oil pressure sensor
Oil level sensor
Coolant temp sensor
I think thats about it. If the donor doesn't match your 99, swap it over.