Strangest thing...is this right?

[Bruce Parker (RIP)]

I was running up my Canadian Mk.1* UC tonight and noticed something I've never noticed before. I turned on the ignition switch and the red dash light went on as is should. Hit the starter, engine fired up and the light goes off as it should. I'm in the back and manually working the throttle only to notice for the first time ever that as the engine accelerated the red lamp stared to glow but very very faintly. The higher the revs the brighter the lamp but even with significant revs it was just barely visible (you wouldn't notice it at all in daylight, perhaps a half volt or so instead of 6). It's all original 6V and wired per the manual.

Is this right?