Camera is out of town at the moment, but the reason why they made two different ones is that the old one was not as reliable and often slipped. The newer ratcheted one was much, MUCH better. The transition years of this was 1967. And there are actually three different versions. The first is the old version with the clockface or telephone dial style with the knurled L-arm and script logo. The second was the first incarnation of the ratcheted version that had the L-arm's hexbolt angled slightly downward. Some had script log and some had block logo depending on how late in the year the version was produced. Also, the L-arm changed from knurled to fluted at this point. The third version was exactly the same as the second version except they made the L-arm hexbolt at 90 degrees for easier access and the logo was the block logo.

Thanks for clearing up the mystery. Drumsonsale.com seems to have many of the parts I'm looking for.