On the car I am working on now (March/April 1970 build) the LH bracket has 'LH' stamped into the area between the bolts.
I wonder if they did that in response to the line worker issue.

That bulletin is funny. Kind of odd that they would go through all the effort to say you may have received a car that has these in the wrong position, and here's a crappy sketch of how they should be installed...but just throw them away. Nevermind, nothing to see here