It could be but, sometimes due to meter limitations and as low of resistance as the windings are, wire temp etc, it's tough to tell. If you're able to truly and accurately measure down to 0.02 then I suppose it could be shorted. Probably easiest way to tell at this point is hook up known good reg's and fire it up. Shorted charge windings won't hurt your new reg's, you'll just not have any output voltage.........However,
As a test and if you don't have your reg's yet, you could fired it up with the yellow wires loaded down with a spare car's headlight for example. Don't get crazy but, quickly bump rev it to say 3'ish K, the light should go from a dimmer light at an idle, think the stator output 11-12'ish volts at an idle and brighten up with perhaps 20'ish volts up in the 4K, 5K range.
You can also open circuit (nothing connect to the yellow wires) check the yellow wires AC output while the engine is running, it doesn't hurt the charge windings or cross couple effect over into the other windings (trigger and such) one bit to run the yellow wires open ended.
Given stator windings are just a perm mag driven coils inducing a potential difference and can run un-loaded, do realize that however running un-loaded doesn't tell you with much accuracy much about any given supply voltage at particular currents per-se. Just a quick and dirty way that tells you you have at least building and collapsing mag fields flying by some amount coil turns (not shorted) of wire creating an induced voltage. You'll use your AC setting of you meter of course
