Alternator question

Here is the upshot, Alt is good. But need some info. With the ignition on I tested the plug at the voltage reg and both wires are hot! Is this right.
I also thought that on the back of the Alt even though they are listed as fields one was a ground because one of the field was insulated.
Also with the ignition on I put a test light to ground and both the field wires were live. If one is a ground which on is it the Blue or the green.
Thanks
AL