not sure i understand the question...but on my '41 6v positive ground system, the positive post on the battery is connected to a stud on the firewall.
and as far a polarity is concerned... it's obvious from reading the posts that it looks to be one of those situations where if you're not confused then you're just not thinking clearly! ha
so what i do in those circumstances is look elsewhere. but even better, i would simply try it one way and then the other, and if a difference is detected i'll know what to do, if not, then it doesn't matter.
Think about it : Positive ground means exactly what it says. The ground is positive. Since closing the points results in grounding the coil, the + (positive) side pf the coil should be connected to the distributor.