Ed, Here is a close up picture of the one with two holes, and why I think someone drilled the second hole.
I have four brackets with the holes in the top and the date codes would be July 17 and August 1 (2 of each), plus the picture we have here of Brian's. Thats another thing pointing in the direction that these may be an early style bracket.
One way to maybe further qualify that is looking in an early MPC to see if Ford listed a -A part number. I dont have an MPC dated mid to late 1968. If there is something like that listed then that would really prove there is an early style since the later parts books refer to a -B part number.