I have one too. Like bgadow I mean to restore mine, but not while it's warm outside.
It's dusty, makes the photo look a little rough. A lot of dust between the CRT and faceplate too.
It's in better condition, in person.
Your channel selector will look like this:
It's the same size/style as the others, just with a flat brass plate bisecting it.
Maybe another AKer will recognize it. The numbers are on a plastic ring
behind the knob, not part of the knob. You'll need one-o-those too.
I have one spare knob. It's not a matching brown. It's the color of the
original brown M&M -- a bit lighter than milk chocolate. The knobs on the set
are very dark brown, like Hershey's Dark.
I guess I could part with it, but I don't think you'd like the color mismatch.
Keep looking first. If no luck at all, it might do temporarily.