Joke from "The Adventures of Brisco County Jr"?

I was watching an episode last night on IMDB TV and thought I'd share this joke...

After running into the bank vault to escape a hail of bullets from Ned Zed's machinery gun during a bank robbery, Brisco, Socrates and the bank manager found themselves locked in.

Hearing foot steps outside the vault they assumed it was Brisco's faithful companion, Bowler. Brisco read the vault's combination through the door and you could hear the clicks as the dial was rotated. But after it was finished the door wouldn't open! So Brisco said "let's try it again" and more clicks from the dial. But this time the door opened, revealing Brisco,s horse instead of Bowler.

"Wow!" said the bank manager, "That is one smart horse!".

"Not really" said Brisco, "It took him two tries"