Thanks, I figured it out. The pistol is there, but somehow the key mapping to fire was mapped to multiple things or something, so pressing the key to fire was doing something else. Not sure what it is, but the pistol icon changed into a white heart.
I am confused by the keyboard config screen which shows some keys mapped to a functionality (e.g., you can map a key to "Dash", "Menu", or "OK") and some keys are mapped to other keys (e.g., you can map a key to "PgUp", "PgDn", or "X"). On top of that, the key PgUp which is also mapped to PgUp doesn't do the same thing as another key mapped to PgUp (?!?!).