I got one like this - bought it for just over melt but it's got some unslightly...something on it. Yours looks great.
All of the classic commemorative half dollars are silver lol... but to date only 2 of the modern ones are: the Washington 250th anniversary (1982) and the Bill of Rights (1993). Why they decided to make the Bill of Rights silver (or why all the other ones aren't for that matter) I have no idea.