Written on the back: "I.D. No. 2349. Ed Marshall (The One And Only) 341-9722. 8101 Limerick Ave., Canoga Park, Calif." So we finally discover the name of the third Marshall boy - and where they lived in Canoga Park!
Can't see much from Google Street View. But I'm betting that house is the same one they lived in, back in the '60s and '70s:
Wow this is amazing bro. You really made a progress there. Keep it up. Finding the history such as this is really a great approach. Nice going.