Looking at section UPC11-13 in the AIM, the part number is 9780422 for the machine screw. Cross referenced on the AMK site, it is a 5/16 - 18 x 3/4 screw, their part number B-12498 and found on page 117 of their catalog. This is a flanged head with a pointed end. I believe the same screw is used for the support bar, but check the AIM. As I recall, this matches what my 11B LOS car had from the factory.