At the beginning when Samantha sets the miniature tree on the floor to turn it back into its normal size, you can see a piece of masking tape on the carpet marking where she was supposed to stand. In the next shot, the masking tape is gone.
At the beginning up until 7:25, Samantha is wearing clothes that make her appear very pregnant. Even her hair style is the same as she wears in later episodes when she was pregnant. In the second half of the episode, she is wearing a slim dress with a belt. Her facial features are also different, perhaps showing she isn't pregnant.