the date code is often on the lower right corner (as it is in the cards I showed), but is sometimes located in the stamp box, or elsewhere on the card...

The first digit of the number is the year, the letter that follows it is the code for the decade:

A is 1930
B is 1940
C is 1950...etc.

So...2A is 1932; 6B is 1946; 8B is 1948...

That's for Curt Teich postcards (I'm not sure I speeled that rite!?)

Here's another card from that corner...I'll let you decode the date