The Fireball 215 is a great engine in a '61 Buick, but I'd be skeptical of the British management and such, Lucas electronics... guhhhhh. Most LR's I have seen spend more time in the shop than on the road. (True for just about any Euro vehicle really)
The Scout has all common as dirt American hardware... AMC engines, GM or Borg-Warner transmissions, Dana axles, etc etc. If it breaks in the woods you don't have to go to a Buckhead dealership to order parts.
As for the OP, I'm sure you have an alternator on there as a replacement for the original generator. Anything with an AMPS gauge had a generator. Alternators didn't catch on until about 1964, and they switched to volt gauges (or just warning lights) when they switched to alternators. Also, don't assume that just because its a Delco its originally from a GM vehicle... Delco components were used on lots of different vehicles back in the day, including some Ford and AMC applications.