if it's 3 plugs, it's a OBD1 ECU/harness. check the OBD1 diagram here
ECU Pinouts, VTEC wiring, & ECU VTEC Conversion Information - HondaCivicForum.com
if your B10 is yellow/blue or orange color wire, then that's the one for your VSS
while you're at it, you can also check the ECU number and see which one your CRX is running to verify that it's a OBD1
Honda ECU List - HondaSwap Forums
if you're engine isn't original, check the engine model stamped on the block. here's a list of honda motors to triple check your OBD1
Honda Engine List - HondaSwap Forums