You can also copy and paste an entire full frame to any other place on the time-line by choosing the position the time-line to copy on the main time-line, then pressing Cntrl+Shift+C, then by going to the target location on the main time-line and pressing Cntrl+V.
Duplicating Entire Key-frames

Spriter Pro User’s Manual version 1.4

This even works if you are copying from a spot in the time-line that is not key-framed. This is  often a fantastic way to start a new animation for a finding an point in an animation you'd already created that comes somewhat close to the starting pose for the new animation.  Just Cntrl+Shift+C to copy the initial pose from an already existing animation, and then create your new animation, make sure you are at time 0 (the very beginning) on the main time-line of the new animation, and then press Cntrl+V.