There’s nothing wrong with that picture. I’m not saying it’s not a refin, but that pic doesn’t provide any proof that it is. Actually the opposite - the neck pocket looks like it should for an original finish. And who’s this “luthier” with the opinion? Just some guy the buyer took it to? What’s his vintage expertise? Sounds like the buyer is trying to get you to give him some money back honestly.
Is there a nice matching “footprint” of residue under the bridge? Do the body cavities look normal? Normally, I’d ask if the solder joints are all original, but on a mid-late ‘70s P bass like this one, you can take the electronics out without breaking a single solder joint, so that doesn’t apply to this one. You need more than just this single pic of the (normal looking) neck pocket to determine if it’s an original finish or not. You have any pics of the body without the pickguard? Any wear or checking on the finish (yes, 40-something year old poly can check also contrary to TB belief)?
