When Elizabeth (Peachy) receives the letter from the Social Security Office there were two stamps on the envelope. 1st the Social Security wouldn't put stamps on an envelope. They would have metered it at the office. 2nd it was obvious the stamps weren't canceled.
When Elizabeth (Peachy) receives the letter from the Social Security Office she opens the envelope on the side where the stamps are affixed. Later when she is talking to Linda Berg the envelope is opened across the top. When Elizabeth is in Chip Carney's office, the envelope is on his desk and it torn on the side again beside the two stamps.