This marks the fourth time that Sam has a gun pulled on him
When Pepe first enters the bar in Mexico, he provides a Norm-ism that translates from Spanish to English as:
Sammy: "Hello, Pepe! What's up, Pepe?"
Pepe: "Nipples, Sammy. That water is very cold! Brrr!"
When Rebecca pulls a gun on Sam, Pepe (Mexican Norm) immediately hides under the bar. The actor playing Pepe also played the bartender in The Three Amigos. In that film, he kept having to hide under the bar every time there was a shootout in the bar.
When Ramon leaves Cheers the translation for what he said in Spanish is: "My heart is sad because I'm going to miss all of the the people of Cheers. My little Carla the most of all. Goodbye friends."
The title refers to a lyric in the song, "The Three Caballeros": "We're three happy chappies with snappy serapes".