I'm thinking about buying a 1938 Martin Committee online, and I asked the owner about its pitch and he said it was low pitched. being low pitched is A440?
Low pitch would be what you want. Low pitch is the standard used today A=440Hz, Whereas the High pitch is A=456Hz (or so) and doesn't play well with others.
All vintage horns (pre 1940'ish) had low pitch or the letter L stamped on them. Also some had high pitch or letter H or a flat or sharp sign (hawkes and co ). Dont buy a high pitch but they are rare
Dave