here's what I figure is correct
couple styles depending on year.
Only took me years to figure it all out...and what do i do with all this info....well I give it away for free

..... and watch prices sky rocket

...oh well.
They don't look that difficult to even make, but I'm a stickler for exact detail on the rare stuff.
The knobs I'm looking for are pretty common on car players also. I may just have to bid on a car 8 track on ebay just for the knobs and brackets.