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I have found some, although limited, information regarding the
commemorative pianos by the Cable Company [010916 MMDigest].

The Columbian Exposition took place in Chicago, 1893, to commemorate
the 400th anniversary of the landing of Christopher Columbus.  The
stickers were placed on the pianos of the companies that attended the
exposition for years to come, whether the pianos were actually there
or not.

In other words, a sticker commemorating the 400th anniversary of the
sailing of Columbus, while it adds some decoration and value, it does
not mean that the piano was built in 1892.  You will need to contact
someone who has a list of dates corresponding to the number on the
piano.  For example,  116150 would be ca. 1907, or 15446 = ca. 1890.