Johans Dart is assembled in October i Detroit! My DC convertible December 13, 1964 and my DC hardtop January 27, 1965 are both assembled in LA and my Dart 2 dr sedan in June 1965 in Detroit!! Nothing make sence!Fascinating and interesting to say the least! The Barracuda build date was Mar 23, 1965 in Detroit. Here is the one from my 65 Dart wagon, build date late Jul 65 in LA. It would be interesting to know the build date of Johan’s sedan and where it was made.View attachment 1715108625
It could be the factories starting getting the new for 66 handles in mid year and started using them when the old supply was exhausted or could yours be a leftover from 64? We will never know!
Your idea of left over might be an idea. I guess they didn't want to stop the line with cost, extra work etc.