That’s an interesting idea, no clue how valid it is, but I’ve been using P basses for years with metal knobs and had zero issues, and the pots have a metal shaft that goes up inside the knob anyway.Nice looking bass-exceot the knobs. I wonder if they switched to plastic knobs to try and eliminate interference and hum? I've read about metal knobs working like an antenna and had considered changing them out on my 5HH but I think I will just go ahead with shielding all the cavities. Good find.