Jason, I really like those White Sox postcards!
For the heck of it, I did a Google search on the name Harry C. Moir Jr. and came up with this:
http://freepages.genealogy.rootsweb....sar/story.html
It turns out that the child pictured on the postcard was adopted by Harry C. Moir Sr. and his wife...the boy was born in 1902.
Moir Sr. was the owner of the Morrison Hotel in Chicago (which included the Boston Oyster House) - the same establishment featured on ad backs of some 1097 George Hull White Sox postcards and 1908 Gringon Cubs postcards.