If you mean after you make a side trip to Early Poptropica, yes. The key lets you open the Inspector's house and discover the thief behind the art robbery.
Other future islands may include side trips there, whether you have beaten it or not. The demo for Ghost Story island had players go to 5 different islands, doing things that were not part of those islands up to that point in time.
you go back on counterfeit island
Once you get the key from the curator, go back to Counterfeit island and use it at the Inspector's house.
If your talking about Counterfeit Island then you get the key and go back to the museum on Counterfeit Island
you have to go back to the guy that sent you
you have to go back to counterfit island and go to the country side.
go in thru the back door
go to early poptropica and go into the art museum there you will find the person and then do what she said then go back to counterfeit island and there i hope i helped
Go back the museum : you have a package waiting for you.
Go back the museum : you have a package waiting for you.
Go back to the museum. You have a package waiting.
You go next to the museum and go to the balloon and leave.
All you do is enter the Pop Art Museum and meet the curator at the bottom left inside. Then you go back to Counterfeit island to finish the quest.