Swapping 98 ecu with 96 ecu, will it work?

[DmaxMaverick]

I thought only 94 and 95 had replaceable chips and anything newer should be sent to Kennedy for a programing upgrade.

Yes/no. He's talking about taking the ECM from one truck and swapping it into another like truck. They need to be "programmed" by someone who can, with the equipment to do it, if an "upgrade" (chip, power program, etc.) is desired. Once programmed, by GM or aftermarket, they will work in any like vehicle/powertrain of same OBD standard.