Digging this up from the dead. I think I figured it out.
K-D Tools bought Mecto, Inc. of Greenfield, Ohio in 1969 per the tool archives. Mecto is a portmanteau word for Mechanic's Tool Co. This company was formed in 1962, and produced V-gullet combo wrenches. Mecto had ties to the Vanadium Tool Co of Athens, Ohio who made nearly identical wrenches. They also show up branded Wright, Cornwell, Mac and probably more.
No direct proof, but it explains the KD v-gullet wrenches.