Hi there! Thanks for reaching out to us. It's tough to say what you have here. I believe the shape of your end profile has been bent out of its original alignment. This is fairly common when a glazing bead has been installed for so many years, but it does make identifying the proper replacement difficult.
You will need to do your best to bend it back to its original shape to determine the proper size. This is of course easier said than done, especially if it's brittle and prone to cracking.
Right now my top suggestions are the 55-212, 55-202, 55-006, and maybe the 55-030. This type of shape is what your glazing bead should look like. You can see detailed dimensions on each product's store page.
