it's not possible to restore an old version of a property using the "restore" link in history page. (I think, but couldn't say it for sure, that this has worked for items ago.)
I get this issue on the property P107 (http://www.wikidata.org/wiki/Property:P107):
I wanted to restore the first version from 29 March because the next 2 are vandalism. But after clicking the link "restore" (http://www.wikidata.org/w/index.php?title=Property:P107&action=edit&restore=16565156) I always get this message: "There is nothing that can be undone here."
It's not possible for me to restore the old version, only by doing it manually.