Our trucks have the ESC. You can find out if yours has been removed by looking t the distributor. It it has a flat plug about 1.5 inched wide hanging off the side, you still have the ESC in place. As far as I know, the carb is not computer controlled. Again, AFAIK, the ESC just retards the timing if the knock sensor (on the passenger side of the block, just above the oil pan) detects pinging.
Swervin has instructions for bypassing it on his site,
www.73-87.com
BTW, I don't have an O2 sensor. I don't think it is supposed to have one, either.
Slonaker