This post is on the garage thumb latch hardware. Ignore the fact that the door desperately needs a paint job, please. It's on the list ...
I will preface this by saying, I've got no idea when this hardware was installed. Probably when whatever the garage was before was turned into a garage. So, then, after there were such things as automobiles, perhaps? Say, 1920's. That would be my guess. Or later, very possibly. In any case, without more ado:
One of the things that prompted this post was a comment on my earlier post from someone who was installing a thumb latch on an outdoor shed and commented that it isn't lockable.
This hardware, though, is designed to take a padlock. This is a photo of the front of the right-hand door, and that ring that you see is one of the two rings the padlock goes through.