The Series Year Does Not Mean That The Bank Note Was Printed That Year
Every single note will have at least one year printed on it. That year is known as the series. Generally speaking, the year on a note is the first year that series of note was printed; it is not necessarily the year that individual note entered circulation.
A great example of this is the 1935 silver certificate series. These notes were first printed in 1935 and were printed all the way up to 1956. They all say 1935 (sometimes with a letter suffix) but very few of them actually left the printing presses in 1935. The same is true of green seal notes from 1934. These were printed until 1949. Unlike coins, paper money is not so transparent as to when it came off the presses. To get a better idea of actual age take a look at the signatures on the note. These signatures will be of the people who were in office when the note left the presses.
Some 1928 red seal two and five dollar bills were printed as late as 1953. Some 1899 one dollar bills were printed in 1922. Just remember that rarity and condition are much more important than age.