I just recently emailed Bob Daisley who played an EB3 on Ozzy Osbourne's Blizzard Of Ozz album. He says that his EB3 had a toggle switch instead of the varitone and that it was stock, no modifications. Does anyone know on here when these would have been produced?
I personally have seen no evidence that Gibson produced EB3s with three way switches. The commonly held theory is that these were the first few. That almost certainly isn't the case. The EB3 was launched to the public at the Chicago NAMM show July 24-27 1961.
I have a letter a month older than this announcing it to dealers (at this stage the EB3 was so new that Gibson hadn't had a chance to put a pic in the Gibson Gazette of that quarter).
In this letter it clearly states the bass to have a 'new 4-position toggle switch'.
So the EB3 started with the four way
So could Gibson have produced a few with a three-way toggle? maybe, but IMHO these would have been custom ordered, or possibly due to a build up of orders and a lack of switches for a brief period.
I am fairly confident Gibson never purposefully produced EB3s with a three way switch. But you can never be 100% sure with Gibson!