I actually did not know. I don't have AD trucks. I was really wanting to know what you noticed. You said you were doing gauges and nothing made sense. That made be wonder. Not meant to belittle you littlebuddie.
I see by your link what you mean. Why you were confused. I don't think it makes any difference which side of the ammeter a load is on. It seems back then they probably wired it that way (47 vs 48) because of where, physically, the wires were coming into ammeter, routing as you say. Or the ammeters where designed differently. You see they had the voltage regulator on opposite sides.
Just be careful, back then they didn't appreciate the value of fuses much either. Make sure you add fuses to everything. Not that you don't know more about it than me.
Ref info: Autometer shows ammeter wired as follows: one terminal from batt, other terminal to everything else but starter motor. "If it does not read properly, switch wiring."
