Casio CT-410V Power Switch Knob

In 1985, I bought my very first keyboard, a Casio Ct-410V. I loved it, and it was a great tool for helping me become a better player. Fast forward a few decades and I rediscovered this keyboard in my attic storage. I’ve gone through and cleaned all of the contacts and outer surfaces. It still looks good and everything still functions great. However, somewhere along the way, the plastic knob on the power switch has gone missing. The switch still works, and the keyboard still sounds just as 1985 as it did back in the day. All I need to get the keyboard back to its original state is the power switch knob. I haven’t been able to find this part anywhere! Can the wizards at Syntaur come to the rescue and help me give a young musician a vintage keyboard?

I have tried scouring the internet in search of a replacement part, but no luck. Even looking for another 410V that someone was selling for parts yielded no results. My daughter is going to enjoy making all sorts of fun sounds anyway, but having this old instrument in top shape would be idea.