I smell a hoax... I wouldn't be surprised to find out that this is simply a carefully doctored replica or re-issue. The pictures are useless for any confirmation. A few of the pictures of Mr. Hayes holding a bass are clearly not the same bass at all and none of them even put the bass and James Jamerson in the same frame.
Then there is the lack of any detailed photos you'd expect to have available to review...neck heel, pot and pickup details...etc...
It's just a pathetic attempt of a money grab as far as I am concerned and I feel sorry for anyone who falls for it.
Call me a "Buzz Killington" if you want and I am no expert but this is my gut instinct.
Hello. Though I am inclined to agree with you, also I acknowledge that there is a third way. Since presence does not denote cause, we can allow the possibility that the seller's bumbling attempts to show provenance (historical photos of him playing any Precision Bass, an affidavit from the present day, etc.) are not necessarily proof that this instrument is not the one he claims it is.
In other words, this bass could be Jamerson's former property, even the very one claimed, even if it were modified other than claimed and/or is being otherwise poorly represented now.
That said, a serious bidder will require real proofs; and so far, yes, those seem not to be available.