Post-reform coinage like the half crown you are mentioning are pretty common and so its unlikely to be faked. If you are concerned about it being fake, weigh it. It should weigh about 14.1 grams.
No, there is no silver in a 1817 US penny.
George Thacher was born in 1817.
George A. Smith was born in 1817.
George Tattersall was born in 1817.
George Jenkinson was born in 1817.
George Abert was born in 1817.
George Baigent was born in 1817.
George Wilkes was born in 1817.
George Webbe Dasent was born in 1817.
George B. Lee was born in 1817.
George Holyoake was born on 1817-04-13.
George R. Riddle was born in 1817.