Interesting find.
The patent number on the all-plastic case is the US version of this Swiss patent:
The inventor, Ernst Graf De Longuyon, had two more injector tricks up his sleeve:
The Supramat all-plastic injector razor:
https://razors.click/patents/US3311975/ (rarely seen)
and an electric injector razor:
https://razors.click/patents/DE1794636/ (probably never made)
He lived in Munich, Germany but most of his patents were assigned to the Swiss Climar AG company.
All these inventions are from the mid-60s, so whatever the blades are, they are probably not very good.
As they are rare, I'd keep them in the magazine. It's probably worth more than the razor