looking at the patina on it, could it be an original one? http://pages.ebay.com/link/?nav=item.view&alt=web&id=151594235802Purchases made through these links may earn this site a commission from the eBay Partner Network OMEGA SPEEDMASTER PRE-MOON CAL.321
isn't this is a decimal (or decimeter) bezel? the seller also says it's an aftermarket bezel. even if he doesn't know firsthand and is just assuming since it doesn't have a tachymetre bezel, I'm inclined to say aftermarket as well, going by the condition of the dial. what you may be seeing might just be poor lighting and dust