I found this info on the web re dating a Kurtzmann piano:

C. Kurtzmann and Co., Boston
1900-13000  1917-61000  1925-86000  1933-97000
1905-25000  1918-65000  1926-89000  1934-97300
1914-46000  1922-77000  1930-96000  1938-107000

I had earlier found much more detailed data that allowed me to date my
Kurtzmann as 1905, but cannot seem to locate that info now.

My upright grand is an absolute masterpiece that I found for $25 at
a neighbor's garage sale.  While the works were remained in excellent
shape despite years of abuse, the cabinet was much less so and required
major refurbishing.  Our nearly Century-old Kurtzmann is now a much
treasured family heirloom, though I suspect my restoration work has
significantly decreased its retail value.