Within my 4-inch crescent style wrench collection (currently 369 pieces) I have the following makers with a broached 12 point 5/16 hole.
J. P. Danielson Bet'r-Grip, Merit Bet'r-Grip, Dunlap Bet'r-Grip, Craftsman, Dowdat (German), Garringtons Red Diamond, Plomb Plombaloy, Wards and J. H. Williams.
I have Bergman and Kilborn & Bishop examples with a square hole.