I came across this article telling about a 1775 Forster Flag going up for Auction back in April of 2014. Incredible to see this flag (given the relatively small size of armies during the Revolution compared to those in more recent conflicts, and that it was longer ago, far less flags were used and even fewer survived).
The article mentions that some only 35 battle flags from the Revolution are known to exist today. Very cool to read about. The flag was also kept in the family for about 200 years until it’s first sale in 1975. The article is: http://www.cbsnews.com/news/revolutionary-war-forster-flag-from-1775-goes-to-auction-in-new-york/
And another on the Forster Flag: http://wgbhnews.org/post/239-years-ago-minutemen-flew-forster-flag-first-13-stripes