Actually anyone can see the original Greek - as most scholars agree it to be. What you can’t see is the original manuscript. There’s a difference between original wording and original writing material used.
But when you have 4-6 different surviving copies, from different provenances, and all contain the same text, it's quite likely that they are faithful to the (unavailable) original.
Actually if a scholar says he can see the original Greek, he's not a scholar after all...