You are totally right about the miter bar. I choose to mill mine to fit. I
have a disk/belt sander and used that to mill the bar - sand & try - sand & try
again - sand try again until I had a good fit with no play.

My jig is only about 1 1/2 years old and it has the second set of holes.
Didn't realize that earlier models didn't have them - thanks for the info. MH