A guy could spend a lot of time looking for the right ones that would have been patented but I would guarantee you, if it was patented, then the drawings are online somewhere. I've found a few of them that were close but since you have the parts in hand you may want to look through these to see if you can find a match which in turn will help you answer how they attach. Btw, they also had a specific tool similar to needle nose pliers designed to fasten them if you click through those patents you'll see those tools invented by Carr.
I'm posting the USPTO and the Canadian Patent Office links because I'm not sure which office your fastener would have been filed in.
Here's the Canadian patent link you will need:
https://www.ic.gc.ca/opic-cipo/cpd/eng/ ... sic_searchOn Canadian site, click on the patent number link to view drawings of each design.
Once you click on patent # then you'll click on "documents" to the far right and then you will see links come up that say drawings, claims and description. Click on drawings to compare.
And here's the USPTO link. Always pay attention to dates cause you're looking for something prior to July 1926:
https://www.freepatentsonline.com/resul ... sort=chronOn the USPTO site you'll see the word highlighted in the middle of the page such as "fastener" or "seperable fastener". Notice the lower the number on the left is from an earlier time frame. Once you click on the word fastener you'll see on the bottom left "view patent images". Click on that link to view each one.
get used to using the back button to go back to the main page with all the patent #'s so you can try clicking on each one.
Here's the one that I found that looks similar to what your clip is.