Should voltage regulator have continuity to its housing?

[RandyT]

Follow up information. Pulled a Kohler 15 amp regulator/rectifier and according to my Kohler regulator/rectifier tester is testing good. So with the pins facing up. From the left AC to then B+ I get .1 ohms because those two pins are bridged. From either the left AC or B+ to ground I am getting 12.98M or million ohms and from the right AC to B+ I get open or no continuity. This is a 41 403 10 regulator.