Screen door hardware

It's tough to tell from these photos, but I think what you're showing me here is a component similar to what you'd see on an 84-100 roller assembly. It might even be an older version of this very part, though with the back end broken off. Give it a look and see what you think. Make sure to check the door for the other part of this assembly just to be sure; if anything broke off, you'll want to get eyes on it before you buy anything, just in case it's different.

Alternate image for 84-100