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A little background on copyright law in effect in 1917. Under the 1909 act, federal copyright was secured on the date a work was published or, for unpublished works, on the date of registration. A copyright lasted for a first term of 28 years from the date it was secured. The copyright was eligible for renewal during the final, that is, 28th year, of the first term. If renewed, the copyright was extended for a second, or renewal, term of 28 years. If it was not renewed, the copyright expired at the end of the first 28-year term, and the work is no longer protected by copyright. The term of copyright for works published with a year date in the notice that is earlier than the actual date of publication is computed from the year date in the copyright notice.
So the fact that Gold medal did not authorized the copyright would not be relevant at this point to your query. If the copyright was not renewed it would have expired in 1945, and if renewed for the second term, then the expiration would be 1973. There was a new 1976 Copyright Act passed, but it would not have applied to any works copyrighted in 1917.
So it would appear that this work is in the public domain and any person can freely use the book.
I hope this helps.