The New Langwill Index lists a multitude of Schusters engaged in the manufacture of musical instruments in and around Markneukirchen, mainly in the 1800's and early 1900's. Unfortunately the quality of the photos on EBay is poor and I can't get any detail as to which of these it might be.
If you're new to horns made before, say, 1946 -- and excepting Dolnet -- you could get horns with a variety of intonation standards. The current most common standards are A=440hz, called "low pitch," and A=442hz, which is a European orchestral standard. The reason I mention this is because unless it's specifically stamped "low pitch" or "A=440" or "A=880," it's probably some other intonation standard and these horns will not play in tune with modern instruments and cannot be made to play in tune with modern instruments. That's particularly the case for instruments that you even think were made before 1914.
I don't know much about flutes, other than those from Claude Laurent, but it looks to me that the headjoint is a fairly old style. Also note that there were Db piccolos.
Any particular reason you're interested in this one, aside from the fact it looks cool?
It looks very well made. Many of those German piccs (and flutes) were made by the same craftsmen who made the Uebels and Hammigs. That being said, I'm a bit suspicious about the length. My Hammigs measure 26 cm sounding length, and his is 25.4 (if that measurement of 10 inches is accurate). 0.6 cm is significant at that length. It seems a bit long for a Db instrument, but it might be tuned at A=444 or 446, which would make it a bit tricky at A=440. Check this out, just in case: