Actually it is and I have one with black metal knobs if you’re interested.
Also you could swap the blend pot then...
I didn't realize that they made several different models of concentric pots (as well as Blend) with a DPDT P/P SW built in. It looks like they require a different set of stacked knobs than I have on my Roscoe (and purchased for this job).
I may just go with the passive tone add and call it a day. The Roscoe Barts are fairly low output passive anyway.

.... and bought more Roscoe basses!!!