Charging circuit - reduced load on ammeter circuit

I have two ‘65 Darts that I will eventually have to address this issue on. I’m not real familiar with the gauges on my cars (yet) or the circuit the ammeter is on, but I do have a question or two. Ammeters are often set up with a bypass, or shunt, resistor to eliminate some of the issues of having an ammeter directly in series with a circuit. For example, the old Snap-On ammeters, prior to their switch to inductive pickups, used a wire-wound one Ohm resistor to feed the meter movement. Does the ammeter in question use a “built-in” shunt resistor, or does it take full circuit load? If not, has anyone ever tried using a shunt resistor in parallel with the meter? It would show charge/discharge, but with less deflection. It might even require a modified meter movement. I hope I’m not asking a stupid question here, and I’ll be the first to admit I haven’t spent much time studying the circuits involved. I do like the information ammeters provide, however, and would like to keep mine if it can be done safely.