Hi! I have a miniature of St. Gauden's first $20 14 karat gold piece along with a certificate of authenticity. I needed a magnifying glass to see the wording. It says Liberty MCMVII and the other side says United States of America Twenty Dollars. I found something on youtube that claims the full size coin is very valuable but could not see anything about the miniatures from 1907. Does anyone have any idea?