if you have an multimeter or volt meter here is an easy way to see if it is charging. Start the vehicle and allow it to idle.
Connect the volt/multimeter to the positive and negitive battery terminals, there should be about 14 - 14.5 volts, now give the throttle a good rip and you should see a small voltage drop and then it should come back up to around 14 - 14.5

1986 xtra-cab 22re
stock everything
1991 bed