In 1922 all Lincoln cents were struck at the Denver Mint, the
coin should have a "D" mintmark under the date. Some of the coins
are missing the mintmark because worn dies and over polishings
caused the D not to strike up well or be completely missing from
the coin. These coins have a much higher value than the regular
1922-D issue.
Many 1922-D Lincolns have had the mintmark removed, the coin
should be seen for a accurate value.