Hi there,
eBay seller barak-janah sells pretty genuine looking GMT bezel inserts. I had a genuine insert lying next to it and couldn't tell the difference apart from the eBay one being a bit thinner. What might be an issue for gen GMT Masters is just perfect for the Noobs, because the insert snapped right in! No modification needed. The genuine inserts have to be sanded down quite a lot to fit...
Cheers
Whatever123
Oh by the way, the seller states he's in Israel but the shipment came from Hong Kong...