I got the following reply from my sword collector friend:
"Most of my reference books make it an English short saber at 38 1/2 inches. Makers marks would tell the final truth, as otherwise, it's more close to German/ French from 1770>.....english short saber that it's closest to is from 1740- 1760.. Mark Cloke has a site, 'old swords' that has some good links to makers marks..."
Looks like we are going to pass on this. Hubby wasn't as into it as I thought he would be. His interests really lie in British Naval history, in Lord Nelson's era. Rev War history had never been of particular interest to him. Too bad, looks to be a nice one.