Earlier in season 1, A is shown painting over the population on the "Welcome to Rosewood" sign...at the end of this episode when Spencer and Toby are in front of the sign, the original number with no paint is seen.
The episode ends with "A" placing flowers on Mrs. Potter's grave which states she lived from 1929-2011 which is impossible as the episode takes place around October-November 2010. This is learned in 2x20 when Hanna tells says the first she and Caleb "got together" was on November 5th 2010, 2 episodes later in 1x19.