alternator not charging

[cjoenny89]

Ok This truck has sat for 20 plus years and now that we are getting close to running it I see that the alternator isn't charging the battery or the gauge is bad. I did see that it has a voltage regulator mounted on the core support which threw me for a loop. I didn't expect to see a voltage regulator on a truck with an alternator. I know on my old tractors that use generators and voltage regulators that when you hook up a new battery or replace a part in the system it might require you to jumper the voltage regulator to tell it to start charging. Is this the case on this 68 Truck? do I need to introduce a spark somewhere to get the system live again or is something bad? what can I check or do to figure out why the alternator isn't showing a charge on the gauge?
Thanks!
Chad