BB driver mount

The pic below is not my engine, mine does have the bosses on the front and the tab for the motor mount, circled, but it does not have the tab on the right, in the square.
Now I know if you want to put a BB in an A body, you need the bosses, and a friend of mine put one in his Dart - but it has the tab in the square and fits fine. He was also able to put a normal dipstick in as it bolts to that tab.
He and I both agree the tab was not cast into the block, and it was not cut off, so lets go with the assumption that we know what we are talking about, lol.
I want to pull the original engine and do a stroker 383 sometime in the future.

My question is: were the BBs with the bosses, and possibly the one tab not there, specific to certain years and/or body types?

db_20050819__3_3.jpg