When did 1973 cs production begin? Would a sept 20th build be a 1972 or a 73?

[execmalibu]

I am looking at a 3.0CS with a production date of Sept 20th 1972... Is that considered a 1972 or a 1973 model?

My other car has a build date of 12/74 and was first sold in May 1975 but has model year 1974 on the title...

With vintage Porsches or MBs the next model year change is usually around August. When does the next year model change for vintage BMWs?

 

[HB Chris]

The VIN is more important. 1973 U.S. production began with 2240391 and 2250319 and were built early November 1972. If it's a euro it could be a `72 but BMW did the same August vacation and cutover to next model year at that time at least for U.S. production. What is the VIN?