According to ECS it was required beginning in January, 1972. The Black Car is sort of an anomoly. It has a body build date of 12B, but didn't ship until January 11, 1972. The VIN sticker NJSteve ordered reflects a 1/72 build and has the additional GVWR and GAWR information required in 1972.
I am still looking for a picture showing typical placement of the Canadian Import sticker.
