43.3k ohms. B+ to case shows 43.3K and one of the AC lugs also shows 43.3k both to case ground. Between the two lugs that shows the 43.3 it reads 0.00k.Is it 43.3 ohms or is it 43.3 k ohms? Also using diode check mode on your meter do you get anything from B+ to the case ground.
With the terminals facing me it is the left and center.Then is a fairly normal reading using regular resistance check. Those two terminals are probably center and the RH one with terminal facing you. Do diode check between any of the three terminals and the case, they should be register "OL" Both forward and reverse.
Or at least the two regulators here checks this way and they are new, never installed yet.