['68OrangeSunshine]

Well only the corner tab on one side is broken. The other side is cracked. So the damage is not as bad as on the guy's station wagon.
That is an interesting product -- thanks for the link -- but I'm gonna try Grumpy's Superglue/BiCarb trick first.
I did it once before when I had to fix the accidently-enlarged mounting hole on my Wiper Knob. I forgot I was driving a '68, and as darkness fell, grabbed what I thought was the Headlight switch. It came off in my hand after a hard pull. My truck was a fleet truck, all-manual, all Standard trim. The Deluxe knobs with the metal dot center are all you can get aftermarket. So I fixed my original.
One of these days, I'm gonna remodel the dash on my '71 GMC Jimmy to be all '68 looking. I already have the manual choke.

Is that an Orange Stepside in your Avatar? I'm nuts for Orange Stepsides.