Interesting in this comment that this person says he once owned the green pp bike.
i find it increasingly annoying and tiring these bikes are referred to as "prototypes." unless i misundertand, which is unlikely, the bike Mr. Dodge is referring to is not the "green" bike. Mr. Dodge owned the blue-green late pre-production, vins CB750-2113/CB750E-2113 which he sold to Mr. World which Mr. World sold on ebay.
regarding "prototype" WHAT prototype? other than the dictionary definition, in the case of CB750 motorcycles produced before March 15, 1969, WHAT DOES PROTOTYPE MEAN? imho, anyone who uses the word prototype to describe machines produced before 3/15/1969 is better pitied than censored. ARRGGHH!
what is so difficult or challenging to refer to bikes built before 3/15/1969 as:
Early Pre-Production - one is known to have been produced
Late Pre-Production - four were produced
there were numerous factory mules before the pre-production bikes, Bob Jameson said perhaps a many as 50.
so this must mean that perhaps 55+ "prototypes" were built.