Looks like a good 'un to me - I have a '58 (pre-baritone) and a '69 (EB-2DC). As you say, original push-button baritone switch has been changed for a toggle switch, finish looks to be original, and it has the pickguard which often go AWOL. Usual top notch Gibson tone woods of the era; eg Brazilian rosewood board.
Bit of a one trick pony - a bass/mids heavy blues-rock tone, but does that trick so well (listen to "Stand Up" album Jethro Tull), and fast neck with the short scale length. Used to be deeply unfashionable, but all old Gibsons seem to be appreciating - Andy Baxter would be selling that around the £2.5K mark. Original case would be a big plus.
Edit: see http://www.flyguitars.com/gibson/bass/EB2.php for more info