as Mr.Sinclair noted, condition is a huge differentiating factor. the maintenance and wear on a piano that old can vary hugely one instrument to another, and that model was one of Steinway's most popular for a long time. you'll find a number of them on the market (depending where you are of course) of varying ages, and there is no rigid correlation between age and quality with pre-1940 s&s grands. if you find an instrument similar to that 1916 at a dealer, much less than about 25k. u.s. would be a decent price for a ready to play instrument ; at the same time paying more is no assurance of a superior instrument with all of the variables. would not be surprised if some had a tag of substantially more, because of their art case or condition, or if a private seller asks for less.
if you are seriously considering a s&s around that size, you should compare M's to the O's and L's, the next size up, which can be some of the nicest instruments under six feet. all three models were designed by Henry Ziegler (d.1930), with the L replacing the O in the mid-1920s in american models, and an updated version of the O in turn replacing the L in more recent times. to my eyes, the extra four inches improves the proportions on how the piano looks. with vintage instruments especially, how they sound and play will largely be determined by the play and care given to them, and the O's/L's will not always surpass the M's, though Ziegler definitely intended that they did.