Photo for wedding party maybe, so Billy didn't pay for it.
Got me convinced. I'm thinking 90% sure its real.
They found the site of the old building with some certainty.
They checked up with diary and stuff with Sallie Chisum's ancestors.
Dated the tin-type photo at around 1878.
Croquet was Tunstall's British sport, so explains that.
Established the subject was 5'8" which matches Billy.
Other Regulators in the frame, known associates.