Kurt,
We're very aware that these cars were made as early as 09A and 12C in 1966. I'm waiting to talk with the current owner on this particular car as it appears sometime in the past they talked to someone else (a very well know pacecar expert) and told them....
And when we are talking dealership replicas (from say 04A to after the race like 06C or later) we tend to think that that it should follow the genral rule of being an RS or RS/SS Convertible, equipped with a bright blue "R" deluxe "732-Z" interior, C-1 or C-4 to be comparable to the actual and pace car replicas, so this is why I have yet to find another C-4 later then our 06C car.
Yes their were quite a few non RS, RS, and RS/SS's that were C-4's, built without the bright blue deluxe interiors, but these do not follow the Indy pacer attributes...