Thank you, I just took another look and gave the large hemmer foot a good hard tug. It's the same as yours. It's two pieces. Cool!
My quilting bar is similar to the one on the upper right but doesn't have a screw. It looks less substantial and appears to be a friction fit for adjusting it.
What is the other bar in the lower right of your picture? It looks like it attaches like the hemmer feet.
Rodney