We're happy to mediate and this is a relatively easy one: The answer is, you're both right, although your friend is slightly more right than you are. There's a tie-breaker third reason, too...
When the Deuce bus went into operation on October 27, 2005, servicing the Strip and connecting it to downtown Las Vegas, it was named primarily for its double-deckeredness. However, the fact that the one-way fare was $2 then (now $3) also played into that theme, as did the desire to tie it in with the gaming industry and the casinos that it links, with deuce long having been slang for two at dice or cards (originating from the Old French deus (modern French deux) for "two."
As to the second part of your question, that we can't answer, although as an interesting side note, "deuce" has a second parallel etymology. Deuce meaning "devil" is of northern German origin, in which "wat de duus..!" meaning, "What the devil...?" has been recorded (in High German the phrase is "was der Daus..!"). Hence, there could be even more significance to your find. Or perhaps someone just dropped their Bible.
