devilof76
Super Freak
There's probably a depression in the sand for where they're supposed to stand. Plus since they both have electronics then they would probably have a peg for each to feed them electricity.
Unless they give him batteries then he's going to have to have a plug somewhere.
C-3PO might have a peg just to make sure he doesn't fall over.
A proper custom stand would account for electical needs, but the fact that R2 has wheels make me pretty sure that he can be removed.