Thanks guys!
@Dave, they made that bowl shape from 48-55 but those were all half bent pipes. 1947 seems to be the only year of the square shank that I can find.
@ Vlodko, I haven't smoked this one yet. I have a few other Kaywoodies from the same era and older with the 4 hole stingers and all smoke great for me! I can't imagine this one would smoke any worse. I've hear many people say these early Kaywoodies could give a Dunhill a run for its money.