1976 GMC C10 Sierra Grande radio knobs
 

I am having trouble finding the black knobs, one with a musical note on it and the other with a loudspeaker? Problem is my radio has split shafts, all the knobs I've been finding have a D shaped hole/shaft. Any ideas? It looks like the original radio.

Re: 1976 GMC C10 Sierra Grande radio knobs
 

Since your radio has split shafts, you likely have an aftermarket radio that is styled to look like the original. Companies like Bendix and Motorola used to make radios that looked very similar to the OE Delco radios. I believe they were commonly sold to dealerships back in the day who would install them as a slightly lower cost alternative to the factory radio. Although they look and fit very similar, the split vs. D-shaped shafts that you've discovered is one of the subtle differences.

I believe these OE styled aftermarket radios did originally come with the OE styled knobs that you're looking for. So they're likely out there, but finding a set is probably going to take a lot of searching.

Re: 1976 GMC C10 Sierra Grande radio knobs
 

I may have some. I will look in my stash to see. If not, I will try and figure out the website where you can get knobs from. I had ordered a few sets for my radio. These are the ones I have now. They have lots to choose from.
Update: found the website. https://www.retromanufacturing.com/search?q=Knobs

Re: 1976 GMC C10 Sierra Grande radio knobs
 

Thank you both very much