How Do I Tell If My Ecu Is For A 5 Speed Or Auto?

This will work for usdm OBD-1 ECUs:

Read the code on it. The 2nd to last # on an automatic ECU will have a 5.
If it is anything but a five then it is a manual ECU.

Jdm OBD-1 ECUs:

Read the code on it.. if the last 3 digits are 900 or 901 it is an automatic ECU.