Definitely hammer. If you look at the rear of the slide , you well see the partially enclosed hammer. If the hammer is cocked you will see the end of the firing pin.
The manual has an exploded view showing the parts including the hammer. Regardless of how it operates it's a heck of a lot better then the original LCP.
Look here on page 29 of the manual:
http://ruger-docs.s3.amazonaws.com/_manuals/LCPII-Ls6Gb8Dsk45.pdf
