$10K for the pair is a great deal considering what he's asking for them individually. I suspect he might let the Series I go for $5K if someone asked nicely. There are some fine instruments on his list, including the Mockingbird bass he has pictured.
Being a Yonkers boy myself, I would believe that the Series electronics probably don't need an upgrade or Bobby would have run into problems by now. No way to know exactly where he lives, but there aren't too many low density areas in Yonkers.
-bob