At the end of episode 1, Deadwood, Trixie gives Al Swearengen a double barrel pistol known as a Derringer. Trixie places the Derringer on the nightstand next to Al's bed. In episode 2, Deep Water, Al picks up the pistol she placed on the nightstand, which is now a small revolver. The same small revolver used to kill Tim Driscoll in episode 1, not the Derringer that Jewel bought for Trixie.
At the end of the first episode we see Trixie place a derringer (a flat pistol without a cylinder) on the night stand next to Al. This is also what we see her handed earlier, and what is in her dress. The next morning, at the start of this episode, the pistol has changed to a revolver (just like the one she used at the start of the last episode.)
In the first season, Al and others refer to the Swedish family that was massacred as "Squareheads". This was a popular slang term used to refer to Germans, Dutch, or Swedes. However, the term wasn't in use until around 1905. Deadwood takes place in the 1870's.