I should think when it was repainted, the control cavity would be sprayed, that's quite normal, but the neck pocket would masked off or covered by a " holding stick " to maintain the neck pocket fit.
This would, as pointed out already, give a clue as to the history of the bass.
Shame it wasn't left silver, I imagine that would make it quite rare and valuable
I wonder if any " home relic-ers " will try out your method of leaving an instrument in a damp gig bag for a month! Did it warp the neck or cause any other damage?
Good luck with this bass, anyway, are you intending to buy it?
If so, I'm sure the seller would send you more pics, including the neck pocket, electrics etc