Here's a link to a site with a lot of info.
Horn-u-copia public forum discussing antique, obscure and out-of-production Brass Instruments
As to the value, $1400 seems pretty high to me, especially if it needs a valve job. I "rescued" and old Pepper cornet, a Standard model, with some minor repair work and a valve job from Anderson's Plating. It was a waste of money - the cornet had serious intonation issues before and after the repairs. Sounds like the one you have your eye on is a more expensive model and may play better, but I'd sure take a tuner with me and really give it a tryout before I spent that much money. The ones marked "Maker" are the better ones - stay away from the imported ones. Another thing to look out for - horns this old are sometimes pitched in what's called "high pitch". Instead of the modern A=440, these horns are pitched at A=452 (or higher). If it's one of those, you won't be able to play it in a group with modern instruments.