The oil gauge would surely go to max. Because the limiter is puttng out more due to a short circuit, the other 2 gauges would climb some. Maybe not to max rapidly but some.
The black powder shown in that gauge was the insulation on the limiters nichrome winding. Thats the 1st sign of a problem before opening the gauge. All these winding start life with a pale gold spiral wound fiberglass insulation. I assume the winding on the limiter shown is shorted to the beam. It's bottled up pretty good. Not easy for visible smoke or odor to get out.
I've found a little soot on the back of the screen where the notch in rim of can is too.
