Personally, i think this will sell.
In this case, i think the seller is adding £4-5k extra for the Pino link, although in my experience in this field, i dont think the Pino link adds any value whatosever in this case, as there's no association. If it was Macca's Violin, or Pino's 'Ray, then it would be different.
With this P, the value is on the rarity of the instrument, and the very early serial number. In the UK in particular, these blackguard P's are extremely scarce, especially all original ones. Granted this one has been played alot, and shows alot of wear, maybe because its an exceptional player?
I think its a lot of money for one though.
I'm not going to get into debates about the value of vintage instruments, as its pointless, as numerous posts on basschat have proven, but, i think a blackguard P in this original condition (Original finish instruments, regardless of how worn, are worth far more than refinished instruments, ballpark guide is double the price on vintage Fenders), would fetch at least £10k in the UK, add to this the very early serial number, and collectors would probably add another £3k+ for that, and then if someone wants the added Pino connection, then you could maybe add another £3k for that. So its not majorly over-priced.
So, all things considered, a vintage shop would always start out punting such a rare instrument at a top price, to see the reaction. The last blackguard P I saw in the UK, was 6 years ago, also at NKR guitars, and it was up for £21,500. So they arent exactly widely available.
Its obviously not for everyone, but its a piece of Fender bass history, one of the very first, and for that reason alone, it will be desirable.
Personally, I'd rather buy a much nicer example of a blackguard, for a little less money, but we all like and want different things. Its a very cool bass though.
Rick.