Direct quote from my Delco-Remy maintenance bulletin for D-R STANDARD 3-UNIT CIRCUIT "A" MODEL 1118825
Bulletin #1R-117, dated 9-15-53:

REGULATOR POLARITY

Some regulators are designed for use with negative grounded systems while others are designed for use with positive grounded systems. Using the wrong polarity regulator on an installation will cause the regulator contact points to pit badly and give short life. As a safeguard against installation of the wrong polarity regulator, all regulators of this type have the model number and the polarity clearly stamped on the end of the regulator base.

I rest my case.
Jerry

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