Given their respective dates, and his apparent age in the photo (looks to be about 20 or so to me), I'd say it was the younger; I'll be able to verify it over the holiday weekend. (BTW, I forgot to mention in my original message that my brother-in-law is a dead ringer for him! They could certainly be brothers if not twins. The first time I saw the picture I thought it was my brother-in-law in one of those "fake" old-time photos you can have done.)
The family information that I had a chance to look at didn't really mention a "Sr." or "Jr." -- the elder was always noted as "El Hannon" and the younger as "Elhannon". I remember at the time that this caused me a little confusion until I sorted it out. Again, I'll have another (harder) look at the papers over the holiday weekend.