The concern with restoring a volume without also restoring the database (or vice versa) is that the two will be in inconsistent states.  See this answer.  In your case it sounds like you are talking about not restoring the whole volume, but just bringing back some individual files, so I think you'll avoid those problems.  The worst thing you might run into is putting back a file that isn't supposed to be there (it was deleted or migrated), but I don't see how that would harm the system.