GM Federal Door Sticker

[GM-26]

Why is it, that some of these decals have the vehicle's build month/year and VIN number and others also include the vehicle's weight?

[GM-26]

Second Picture

[DaJudge]

I think that started in 1972. The 69 - 71 cars I have owned just had the VIN and the month and year of manufacture. It could also depend upon the plant in which they were produced.