If these are hybrids, it still means that the species of the Pinta Island Giant tortoise is dead. However it does mean that at some point prior there was a split and these other tortoises from the wolf volcano share a common ancestor with lonesome George. Unless of course they do manage to find some pure Pinta island samples. I am thinking that would be unlikely.
This is really not all that unusual though, such separation of species is common, it is basically a core principle of evolution, along with the extinction of the ancestor species that was not as ideally suited to survive.