I couldn't find the photo of the other side, but it is from a Masonic Chapter in Winthrop Mass. Dated 1889, I believe.
it would be typical to have the Chapter's Charted Date Shown but that should not be construed as the age of this Penny or mint date. Is there anything on the other side indicating Winthrop Mass?
If memory serves, the G stands for "grand architect". The Masonic representation of each Mason's personal idea a God, or creator of the universe, or what have you. I don't thing you have to subscribe to a specific spiritual ideology, you just have to subscribe to one. Disclaimer: not from a Masonic family, I just once asked a friend who was one.