ok...I gotta confirm that.

When I lifted the data from the tag a while back, I did so by rubbing a pencil on a piece of paper held over the plate. I can't make out those 3 characters so I'll go out to the garage tomorrow.

I can say though that the build date would be before June 20, 1968 because I still have the original owner's manual and protecto-plate. That date appears on one of them.