Yep, you guessed it. I'm still reading Rin Tin Tin: The Life and the Legend by Susan Orlean.
I've seen some of this 1930 serial, and it's pretty rough going. But it does feature the original Rin-Tin-Tin (at least in close-ups) and it produced some pretty cool posters.
More Overlooked Films (and maybe some other dogs) at Sweet Freedom.