How do you date old blue Mason jars?

So if you have some old jars, how do you know their true age? If you have a Ball jar, you can date most of them just by looking at the logo. Every few years, the Ball Manufacturing Co changed the logo and if you compare yours to a reliable chart, you know how old it is. All you need is a chart like the one below.

Are Ball jars the same as mason jars?

A Mason jar is a molded glass jar that is originally used in canning to preserve food. Other common names for the original Mason jar include Ball jars (after the Ball Corporation), fruit jars and simply glass canning jars. All Mason jars are not created equal.