No, a RAID array doesn't keep earlier versions which are increments from the last major backup. A RAID array is a way of reducing exposure to HD disk failure, but doesn't allow going back to (slightly) earlier versions of files.
I don't see a requirement to go back to (slightly) earlier versions of files in the original question, indeed just the opposite.
There would be issues of having multiple file versions, but that's something that authors of file-backup software have found ways of dealing with.
If I have a doc that I keep updating I tend to do a "save as" and add v1, v2 etc to the title so I know whats what.
