I looked up "Putnam Light Infantry" and it was:
Company G, 12TH Regiment Georgia Volunteer Infantry.
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The flags for the war are at the Georgia state Capitol. here are a couple of links.
http://www.sos.state.ga.us/museum/flag_info.htm
http://www.sos.state.ga.us/museum/html/flagcollection.htm
Here is a link to the people who run the musuem at the capitol. You can send them your questions. Who knows maybe they might want to buy your flag.