Help to decipher a mopar vin number
was looking at the GTS registry
http://www.gtsregistry67-68.com and the first entry is LP23H72320*** and states it was built April 24, 1967, that fits my estimate very well.
Also I agree that the sequential unit number was not specific to a particular car model line etc, might have been a Dart Convertible built then 20 other models between the next Dart