What is this metal called?

[benbuilder]

I am putting this Tudor together. 1930/31.
I need to repair these pieces, left and right.
This is a picture of the driver side below the rear window at the subrail. i think it might hold the window when its in the down position? Not sure, as i bought this as a project.
Pass side is worse. Is this reproduced? I looked in the bigger catalogs but could not find them.