@Peter BENSCH Winner! Peter is right, L5150BN Pin 2 is internally connected to the thermal tab/pin/pad in the SOT-223 package. Had to lift a pin on a production assembly, but worth it to get the answer.
@Peter BENSCH Thank you for your response, but this is in conflict with a direct case/ticket I put in to ST Customer support. This was Customer Support response: "To answer the question about the thermal pad, if its not specifically called out as a...