I am thinking that things that pertain to the curse are magical, meaning the curse itself contains the magic. I think the characters caught within the curse have been stripped of their magic. So the heart transported with the curse, just as Mr. Gold’s “please” was transported. Perhaps Regina customized the curse in that way before she enacted it. Certain things containing magic were brought to SB, but I still am not of the opinion that she or Rumpel have any active magic at this time, even though they have knowledge.
Don’t forget though that Mr. Gold said he had buried the knife because when Emma came to town he saw things changing. I took that to mean he wasn’t certain if certain magical items were going to “find” themselves with magic again. Thus hiding the knife from Regina. He said he didn’t want to take a chance. So obviously, he himself doesn’t even know how far reaching the affect of Emma’s appearance in SB is going to be. He must think it is possible she will bring the magic that is in stasis back to life, particularly in some of the objects that held magic.