Diane -
Well I asked for a RAK - random act of kindness - from a fellow researcher, Linda Thompson, who subscribes to Ancestry.com. The above two images are from her via Ancestry.com
The interesting thing here is that we have not yet found an image from 1918. So, we nee to figure out a bit more about where he might have enlisted.
This shows that he enlisted prior to 1913 and was discharged in 1913. He then signed up for the draft and noted that he was a veteran. That could be another option - he could have called back to the service, but I don't know if that was a policy back then.
Was there any reference in his obituary? What is on his tombstone? If he has a military tombstone it may show a regiment.
Hope this helps.
R