Hot Rods eellco belts

hello all new member first post , looking to see if anyone has any info on my eellco saftey belts , ive had a few sets but these are the only cam lock ones ive come across so far just wondering date/era

 

After 1964. (it has a zip code)

 

Cool belts, but I would only use them for show. Weathered like that, it's hard to imagine they'd stand up to what they were designed for.