Sry - that's not an original 1872 concert grand..
Not because of the colour. Not because of the legs.. (see below..)
It's because of the third pedal, the sostenuto. This was invented by Theodore Steinway in 1874; he put it in the square grands and a year later into the concert grands. As the first sostenuto systems in the concert grands were also fitted to the wall, I would be very much interested in an inner view of the mechanism..
Most probably it is also converted in another item - to the capstan use. Capstans started in 1875 (march, 1st case whose mechanism later got capstans), also an invention of Theodore S. Patd 11/30/1875. Elder versions originally had the "rocker" action. In this a pushrod connects the key with the repetiton.
Rich - ;-) 88 keys started in the concert grands in 1863. (OT the earliest 88 key instruments of Steinway were the bigger square pianos, they named them "square concert grands". They partly got 88 keys yet in the very first year 1853.) Every Steinway concert grand (>8 ft.) since 1863 has 88 keys.
At any time in these years 1870-77 Steinway begun to offer also black grand pianos. Plain versions, without carved wood. Maybe yet with the "spade" legs. It started 1877 the latest - maybe earlier - that the customers had a chance to order other than rosewood veneer. I own an early Centennial D concert grand built 1877 which is plain and was delivered in such original ex works cond. named "style V" - different to the "style IV" (rosewood, cabriolet legs).
So the 1872 grand piano is modified.. Sostenuto. Maybe the case is built originally without rosewood veneer but black spray on maple?
The curves of the keyboard arms show the "classical" Erard V pattern.
Transient part of that very bulding year 1872 was the duplex scale. Cit. Roy Kehl (p.107):"1872 5/14 patent: Duplex scale for all grands, cabinet grands and square grands (88-note trichord-treble squares)"
Has it the duplex scale or not? The invention was done by Theodore Steinway and tested with his friend the physicist Von Helmholtz in Berlin who had got a concert grand in 1870 with some experimental modifications @ co-sounding (non-speaking) string lenghts.
Serial no. of the concert grand? Steinway Queens yet asked for a PDF email copy of the corresponding delivery book page? (ask kindly @ Mr. Kirkland.)
I bet: it is a "style III" concert grand, the savvy version compared with the carved beautiful rosewood style IV concert grand type. Plate with rhomboid sound holes. Rocker action originally, no sostenuto. Spade legs (straight) and lyre (straigt) but two pedals originally. Later converted to the capstan action, maybe together with this the sostenuto and third pedal w. other lyre was built in.
If it is an early original Steinway Sostenuto version: it is valuable - to extract it out of the 1872 grand and put it into a fitting concert grand with the old symmetrical string field layout 17-18-18-18-17 - beginning 1875, ending 1884 - with due respect to the original ex works delivry statuses. To take from the 1872 grand what hasnot to be there, and to giveit to grands which should get back their "original stuff".