I have an old copy of Index to American Genealogies, compiled and originally published by Joel Munsell's Sons, whose title page says it is a reprint of the Fifth Edition, 1900, with Supplement, 1900 to 1908, Genealogical Publishing Co., Inc., 1979. It lists 10 sources for the name Munsell, but none is military. Probably of most interest would be Munsell Genealogy (1884), 150 pages; NEHGS Register, xxxiv, pages 246-251; and Stiles' History of Windsor, CT, ii, 510--5 (that's how it is listed, unclear if it means 510-515).