Justice,
They do not appear to be reproduced as you have found.
One good note: The same part was used on the vast majority of both Trucks (under 1T) and Passenger cars alike from 1936-1950 in both front and rear Huck brakes (with a few exceptions). See the screenshot from the 1929-57 MPL below to help identify possible donor vehicles.
Basically then boils down to just a couple options:
1 - Search web listings (Craigslist, FB Marketplace, eBay) for folks trying to sell old "Huck" brake sets. Many folks opt to upgrade their "Huck" brakes for newer styles Bendix or disc brake set-ups, selling off their old parts.
2 - Put an ad in
The Swap Meet Truck Parts Wanted. Some of our fellow 'Bolters more likely than not may have a few hanging around that need to find a new home???
3 - Search our own
Swap Meet Truck Parts for Sale or
Swap Meet Other Online Sources for folks offering to sell what your looking for.
Am sure others will chime in here, or reply to an ad you may post to help you find what you need.
Good luck in your search.
Dan
