the only OBD1 ECU's I know of that have knock sensors are the P13(prelude), P30(92-5 DelSol), P54(EDM Accord), P61(92-93 GSR), and P72(94-95 GSR).

P74 & P75 were the non-GSR ECUs. no knock sensor in those.

BTW if the ECU needs one, the car will start and run. But the CEL will be on. Code 23