Great picture!  Such history... and to be of your actual family - Priceless!

I think you're right about his being in the National Guard.  In 1911, regular Army would have a 1903 Springfield.  I'm surprised that it has the Krag sling, since the 1907 sling was available for a few years at that point (unless the Guard units kept the Krag slings on the Krags).