Warning: Very long-winded reply approaching.
Sturz Brothers pianos were established in New York state in 1871, and seem to have the reputation as "[Sturz Brothers]...pianos and piano-players are distinctly high-grade instruments" (per http://www.bluebookofpianos.com/).
I can't find any information as to when they ended making them.
All of which is great, but:
Be aware when dealing with antique pianos:
Many of the old (say, 1850 to 1940) pianos were made by companies that are no longer in business (failed, or bought out
by a competitor), or companies that built the instrument under another name.
Pianos back then were not really mass-produced, they were hand crafted- and each manufacturer made their piano very
Short Version: there will be parts that will work on only that *one* model of piano, so getting parts will be difficult if not
Long Version: Musical instrument craftsmen (craftspersons?) love to innovate, for a variety of reasons: they may find a
new way, for instance, to connect the key to the hammer that strikes the corresponding note. It might be a better way to
do it, or, more often, it was to come up with a cheaper way to do it.
The point I'm making is that your Struz Brothers piano will have parts that are totally different from, say, a piano made by
either Krakauer Brothers, Doll, Jacob & Sons, or Mathushek & Son Piano Company (companies that started around the
same time as Sturz Brothers). The parts may vary from one year to the next, or even one model to another.
So, if your Sturz Brothers piano needs a key replaced, or the harp has bent under pressure, the soundboard is cracked,
or any number of things that can plague an old instrument, you'll need to either
A) find someone that is willing to sell parts from a similar model (if they're parting it out, it has more problems than
yours does), OR
B) you'll need to have the part manufactured from scratch by craftsmen that specialize is rejuvenating old pianos. This
will be expensive far, far beyond what the piano is worth- and these craftsmen live very well, BTW...
Last Caveat: Upright models sell for much less (and the term "Upright Grand" was just an advertising phrase, there is
no such animal.) Uprights (spinets particularly) sound very... tinny, is the best description I can think of. Tinny like the
toy piano your granma gave you when you were five- remember, the black keys were painted on? Tinny like that.
So, unless the piano is a Steinway & Sons, a B?sendorfer, or a Fazioli, don't count on huge offers for your instrument.
And if it came to you from your great-aunt Tilly and you can't bear to part with it, that's great, I understand sentimental
value. Just know that this will cost a great deal to bring to playing condition.
I'm often told "But the keys all work, the pedals are still tight, and the tuner told me that it's not a bad piano!" All this is
true. But please remember that professional buyers know all of these potential pitfalls won't offer much, and the guy on
Craigslist that needs to replace the piano for Great-Aunt Tilly can't afford much.