Semantics can be a real tough issue. The word classic with a lower case C can mean almost anything, like beauty it is in the eye of the beholder. The use of Classic with an upper case C is usually accepted to be those autos recognized as such by the Classic Car Club of America. A 1915 Oldsmobile is a good car well worthy of your interest and accepted by the Horseless Carriage Club due to date of manufacture but rejected as an applicant to the CCCA as being a horse of a different color.
Basically, a CCCA Full Classic has to have been made between 1925 and 1948. That's what CCCA designates as The Classic Era. The Club does accept some cars that were built prior to 1925. That's because virtually the same cars as the 1925 versions were built prior to 1925. It's pretty hard to tell the difference between a 1924 Packard and a 1925 Packard. The same could be said for a Rolls-Royce and many others.
The car in question must also be on the CCCA's list of Accepted Classics. Although Oldsmobiles were very good cars, they don't happen to be on that list. It might interest you to know there is one Olds listed in the Club's Roster. It was accepted by the Classification Committee because it has custom coachwork.
Any member of CCCA can submit a car for consideration for Full Classic status. Custom coach work, done by a recognized body builder, that was originally fitted on a non-Classic chassis is one of the variables that is allowed. If you are going to make an application, it does save a lot of time and frustration if it is for a car that fits closely within the Club’s stated guidelines.
Since Oldsmobile made a very different car in 1925 than they did in 1915, the earlier version would not qualify, even if the later Olds was acceptable. That’s not to say you shouldn’t enjoy your car or that you might not enjoy membership in CCCA. It’s a great car, just not a CCCA Classic.
By the way, you don’t have to own a qualifying car to be a CCCA member.
