Yeah, it seems the repop houses always get things wrong.
But, I did a little detective work and found that the original part number (7752485) was superseded by part number 1732326 in 1972, which was superseded again in the 1980's by part number 20348200. And guess what, 20348200 is still available at your local GM dealer!!!
Now, remember, superseded parts may not be "exactly" like the originals. Especially one that's been superseded a few times. Usually by this time they're just a handle that will "fit"! But you might want to check it out anyway. Also remember that "service" parts may not be "exactly" like "production" parts. The service department had the responsibility of finding something that would fit. They didn't care if it was exactly like what originally came on the car.
However, that being said, I did a search on ebay and found two sellers with the 1732326 parts and several with the 20348200 parts. I also checked GM Parts Direct
and they have the 20348200 in stock, but they're NOT
cheap!! You might want to check your local parts department and see what they want for them.