Revealing mistake: In addition to Samantha, Elizabeth Montgomery also played Serena. In scenes where both characters appeared, Elizabeth would face the camera and play one character and another actress, Melody McCord, would play the other with her back to the camera. But in this scene, when Mr. Beams tells Serena she has a luncheon date with her intended at the rotisserie, Melody (portraying Samantha), with her back to the camera, inadvertently turns her head, revealing her face.
Revealing mistake: At the end of the episode, during Serena and Samantha's second meeting with Mr. Beams, in the wideshots of the two women sitting on the couch and also when they're both poking their heads through the doorway, Serena's body double actually appears face-forward. Additionally, in the closeups of Serena and Sam on the couch, both are played by Elizabeth Montgomery, and we can see the wall's color difference behind them due to the use of the split-screen technique.