I emailed the seller about provenance and he said he is as sure this is an Indianapolis ABC's pennant as REA was sure this was a Boston Red Sox pennant and not a Spartanburg, Brantford, Danville, Superior or one of the many other "Red Sox" teams that existed in 1912.
http://www.robertedwardauctions.com/...2010/1238.html
I'll give him credit though he did not hide the fact that he bought this off of ebay just recently and told me exactly what the first seller mentioned about the pennants.