Storm Window Latch, no markings or name on the storm window.

Thanks for posting. I'm afraid I'm not sure if we have an exact match for this slide bolt, but the only way to know for sure is to remove your old ones so the dimensions can be properly compared to some of our possible replacements. I've listed a couple of such replacements on this page here, and reproduced the diagrams below. Compare your old slide bolts' dimensions to these candidates, and see if you think any of these could work for you.

Alternate image for 91-140

Alternate view of 91-140

Alternate view of 91-140

Alternate image for 91-130

Alternate view of 91-130

Alternate image for 91-142

Alternate view of 91-142

Alternate image for 91-158

Dimensions for 91-158

I agree, our 91-158 does appear to be the closest match, though it's not identical. While I think it's worth considering I cannot guarantee that it will work. The spring designed to work with this latch is our 91-102.

The unfortunate fact of the matter is that there's a good chance we simply don't have anything that will match exactly. Storm windows in general have been dying off for decades and replacement parts are getting harder and harder to get a hold of. That's just the reality of the industry right now, unfortunately. Just something to keep in mind as you move forward on this project. Even the 91-158 is under a limited supply. Once those sell out, it won't be possible to restock them. They're just not made anymore.