6 Volt generator mayhem...

[chevylookin]

Hello guys, been a while...
I have a 52 1/2 ton pickup ive been tinkering with for a while. Got an issue with the charging system. Has a 58-59 235 but still has a long 6 volt generator/regulator battery. Just picked up a new 6 v battery and regulator. Problem is after many tests to figure whats goin on, battery and regulator even say battery is charging i think...
Anyways, if i disconnect the 3 wires from the reg, and hook up the volt meter, it says generator is putting out 4.5 to 5 vokts at idle. If i rev the engine to 3-4k rpm, the meter reads 15-17 volts. Os this normal for a 6 v generator?