William Willcocks in the Military

William J. Willcocks was our grandpa Harold Willcocks's father. He was born in Quebec, Canada and came to the US in 1898 when he was 18 or 20 (depending on which source for his birth date is accurate). According to the 1910 census he worked on the coal dock in Ashland, WI. Later he became a structural iron worker building bridges and had to travel to larger cities, such as Detroit, and stay there for weeks and months at a time.

But before all that he was in the armed forces.  On June 29, 1901 he joined the US army and was in the 19th Battery, Field Artillery stationed at Fort Riley, Kansas.  

He was given a handbook to guide him.

William Willcocks
19th Battery F.A.
Book No. 1

In the back of the book he kept a ledger of the clothing given to him and the cost of each item.

He made the rank of Corporal before he was honorably discharged with Excellent Character on July 28, 1904.

His Veterans Administration Identification Card says he was a vet of the Spanish American War. I know that war lasted for a few months in 1899 before William enlisted, but I don't know enough about military history to know why he was considered a vet of that war.