Beautiful, fantastic. You could sit that in your lounge and admire it forever. While building it into a car is the whole point, it is still great to see it on its own.
The tab welded on the sump is for safety wiring the drain plug. At least that is what I have always used them for. Hopefully it isn't for some really technical purpose and I am just to dense to know what it's real purpose is....
The tab is for mounting the oil temp line, that is the oil temp boss in the front, the drain plug is mounted lower and in the rear of the pan beside the cutout for the starter motor