Here's Matt Dillon before he got an Ojala rig. Gun looks 7 1/2" but in even earlier shows he had a 5 1/2" gun in a shorter holster. His gun shown here in both pictures is a Colt Bisley with SAA parts put on it. Look how the frame is higher where the backstrap screws on. Also, it's the gun he switched to real stags later.
Edit: in this link featuring the top sixgun, the serial number is different than the one with the real stag grips. It's on that paper it's laying on. But both have Bisley frames. Weird.

"Gunsmoke" Colt Single Action — Old West Events