Thanks for the pics! Do you think we could get a video or some recordings of how it sounds?
From the looks of it (I tried researching it too), it seems to me like it's an independent horn maker. There are a LOT of them, especially in Europe, and most of the old ones went out of business a long time ago because of increased demand and/or larger corporations bought the smaller independent businesses (like Conn-Selmer bought Benge when they were greatly dimishing). It also looks a little French, and maybe this horn maker refurbished it or made some modifications. Since we don't know, well, anything about this horn maker, the best guess I can make from the number of the horn "2439" is that it's an intermediate horn and maybe the production number 'the 2439th horn' (since it doesn't really indicate the size of the bell, bore, etc). From the mouthpiece perspective, it looks very French to me since it looks like the way Couesnon made their very first horns/mouthpieces.
You should cross-check with other older horn makers and maybe find some similarities; her/his business could've been bought by another; you can check out this list here:
http://www.trumpetherald.com/forum/viewtopic.php?topic=5873&forum=7
Another good idea is to subscribe to TPIN (Trumpet Player's International Network). It's an email subscription list that puts you in touch with millions of other trumpet players. You can ask this question there and see what other say. I post there sometimes and I get very helpful and informative responses, even from current professionals!
Hope this helps, and good luck!!
belltrumpetplayer19
