How do you release an ignition cylinder

I'm trying to replace an ignition lock cylinder on a 1970 Plymouth Duster. I have the column down to the shaft bearing housing. My repair manual says to press a spring latch through an access hole but I can't find such an access hole. The illustration also doesn't look much like mine because the manual covers five years of models. I believe I have an early model 70 because it came with a 1969 model dash bezel and AM radio. Does anyone know the correct procedure?