But, a paper receipt is all that differentiates print #1 from #1005, and #1 is usually more prestigious. And even if those prints came off the machine in the other order, the actual artist is still attaching significance to one of them over the others.
NFTs are a way of saying that my identical print (file) is really the special one. Or that I'm special for having it. Or whatever.
So yeah, by looking at both NFTs we can clearly determine which is authentic.
If they're supposed to be unique, as opposed to 'we both sponsored the same art', then there are easy ways to ensure that.
If Beeple creates another NFT referring to the same work, then he is simply creating a second edition, in the same way that an artist can create a run of prints limited to 10, and later decide to create 10 further prints.
If someone else creates an NFT claiming to represent Beeples work, then this is like me selling my own unauthorized Robert Rauschenberg print, which I might find difficult to find a buyer for, though with enough talent, maybe not impossible.
In any case, the NFT is merely a digital equivalent of a print.