TRIPLEX windows manufactured in the 1950's through the late 1970's can be dated with the 'TRIPLEX CODE' stamped into the glass.
Assuming that your car has the original glass, it can be used to fairly accurately date your car.
If you know the decade your car was produced, just look for two dots in the TRIPLEX logo on the glass.
One dot above T, R, E, or X gives the quarter of the year the glass was manufactured:
T is Jan, Feb, March, R is April, May, June, E is July Aug, Sept, and X stands for Oct, Nov, Dec.
To find the year of manufacture, look at the nine letters in the word TOUGHENED.
One dot below a letter gives the year of the decade:
T is 1, O is 2, U is 3, G is 4, etc.
If there is no dot, the year is a zero.
This code also works if you have a TRIPLEX window with the word LAMINATED instead of TOUGHENED.