"Skids" O'Toole First Deck

I don't understend. If you have only one Revised Core Set how can i pick 2x Derringer or 2x Machete and others?

@Daimand The Revised Core set should have at least 2 of every non-unique card, though some are in the others' decks. (But if you're playing solo, the others don't need their cards.) For example, in this deck, I was able to recreate it using cards from Skids', Roland's, and Wendy's default decks.