Summer Water Temp Baseline?

I traced down the wire to the Auto Meter, under dash gauge and the sending unit is screwed into the block on the lower right side near the oil filter/oil pressure unit.

Someone has removed the block plug and installed the sender there.

I would think the water temp would be lower than at the top of the heat exit/outlet into the radiator than in that rear, lower area of the block.

Am I thinking right here?