Music Box Tune in "The Night of the Feathered Fury"
The sound of "My Grandfather's Clock" being played in the toy shop in Season 2, Episode 17, "The Night of the Feathered Fury," is unquestionably a Fisher-Price Tick-Tock Teaching Clock. I had one at the time this episode was made. Several models can be observed in YouTube videos, but they all make pretty much the same sound, which is unmistakable.
Note: it should still be around 1875 here and the song wasn't written until 1876 but whatever.