Re: Star Trek. Cue eyeroll. (Great episode, but that's as far as that goes.)
However, as Doc's third cousin (maternal side), I approve of this replay.
The one flaw with most portrayals of Doc is that he was actually a very small man— about 5'6", and very, very gaunt due to the TB which eventually killed him. (Most actors cast in the role are instead 6' tall or more.) Supposedly, he dropped the coach gun after firing it because it was too powerful for him to handle, and switched to at least one pistol (possibly two; he was ambidextrous and an equally good shot with either hand, or both at the same time). The coach gun supposedly belonged to Virgil, who loaned it to Doc for the fight.
I don't think he owned a Colt Army— he did, however, own an 1851 single-action Colt Navy, converted from ball-and-powder to cartridge. Wyatt's accounts assign him the Colt Lightning as well, though it was a finicky gun. He also owned a double-barreled derringer, engraved as a gift from his paramour "Big Nose Kate," though it's unlikely he used it in this fight.
Of course, the whole thing is caught up in legend, and who knows what accounts are actually the truth… the line from Sunset certainly fits!