I know the OBD I generation of LS ECU's were called P75's. I don't know if that's true for ECU's after '96 or not. What year car is the swap going into? It's best to match the ECU to the year of car since your going to have to re-use your Civic wiring harness anyway. The '96-'98 cars have slightly different harnesses than the '99-'00 Civic's (sometimes called OBD IIa and OBD IIb respectively).