Alternators have regulators, but they can be internal.
You need to know where the ammeter is fitted in the circuit. The POH will normally include a wiring diagram that makes it clear. If the ammeter is in the alternator output (usual for Pipers) then you'd need to switch off everything to see what current is being pumped into the battery.
If the battery is in reach from inside the cockpit, feel it after a longish flight to see if it is hot. It shouldn't be. Hot = being overcharged.
The ammeter in our Arrow is so inaccurate it tells you little more than "not a lot", "normal-ish" and "lots". We know the normal in-flgiht position of the needle (once the alternator has replaced the power used to start the engine).