Maybe I don't see this clearly yet but. Of course you can weld it. That is plenty thick. Why not? Come on, Just weld it and then work it back to the configuration by die grinding and/or drilling. You have NOTHING to lose, by trying, if you are going to throw it away. You need to remove the glass.
Can you cut back past the half hole, then make a piece with a hole drilled in it and weld it on. You should probably have the two pieces (frame and glass frame) "mated"/held together and pivot pin in hole, stud mounted with spring and nut.... as you weld. Tack and test rotation, then final weld.
Option 2.
You can grind off the entire remaining piece, make a whole new piece and weld or rivet it on. Where is everybody's will power? This is a piece of cake compared to many other fixes. Push the go button.
Option 3.
Wait for a painted one on Ebay to appear. One will, eventually..........or on here as Tim suggests.
Your added pictures are appreciated but way to far back from subject area.
