Yes, I think that Rumple and Jefferson’s convo about the slippers that went to a land that Rumple wanted to get to had to be the slippers from Wizard of Oz, and I doubt they’d have just dropped that mention completely randomly, I believe they were setting up a future storyline where we see Dorothy. The Wizard and Dorothy is currently my fave theory as to who Greg and Her will be.
This isn’t strictly a spoiler, really more just speculation, but Jane Espenson recently randomly (or was it?) tweeted this:
…and I wondered if perhaps she'd been writing something Dorothy related for the show, (though she told someone who asked that it had been nothing more than a random thought that popped into her head). Also, she recently mentioned in an interview regarding the identity of “Her”: “I think that's the kind of thing you should expect to find out probably this season.”