I was going to say I doubt that the one they've found is as old as the original, because it doesn't have the columns: copies before a certain date have them, and ones from after don't, and the story was that the painting was cut down to fit a frame at some point.
Wikipedia, however, says there is physical evidence (which I won't go into here) that the original never had the columns, so never mind.
Odd that some find cross-eye viewing easier. I can't make it hold still that way. I learned freeviewing years ago, and it's way easier than carrying a viewer everywhere just in case I run into stereo images.