How do you verify 1804 liberty head silver dollar?

There are only a handful of genuine 1804 silver dollars known. The easiest test for a non-professional to do is just take it to a reputable coin dealer for an evaluation. Chances are, you've got a copy. Before you do this, look for a "COPY", "REPLICA", "R" or "C" stamped in the coin, if you've got one of those you have a fake without a doubt.