Wow, nice vid. Makes me wonder, though.. was Billy inspired by Rick Laird? Rick used his mud'd P (ash/rosewood) around '71/'72 I think..
Your axe is quite similar to my '74 P, although I only have blend and tone - and wound down the mud to match the 10K5 P pickup.
It was my main bass (along a Grabber) for close to 20 years, but I hated it in the end and went all SG/short scale.
The Rick Laird thing was an attempt to honor this bass a couple of years ago, and make me justify keeping it, but I still don't use it
and will get rid of it this year I'm afraid
Sorry for disturbing your thread Scott, but the maple/ash/mud theme got me going