"do all powertrols have the pump between the distributor?" ---- No, all powr-trols on A,B,&G tractors came from the factory with a pto driven pump located just in front of the pto seal housing. The pto had to be engaged to use the rockshaft or hydraulics. The governor driven "live" pump was developed for 50,60,&70 tractors. It could also be retrofitted on A,B,&G tractors.
how can I tell if the pump is turned on or off?" ---- The "little rollpin hickie that turns" is what turns the pump on and off. Look next to it and you'll see On and Off marks cast into the pump. ALWAYS turn the pump on BEFORE you start the tractor.