I figured Will would recognize the ring once he sees it on Hope's hand. But here's my question. Do young men even pay that much attention to jewelry? To the point of being able tell the difference between one ring from another? It's not like Hope's engagement ring is that distinctive. It's just a big diamond, like most of the Salem women wear. Would be different if it had been a big colored stone, like an emerald, ruby or sapphire.
There's an episode of Friends where Chandler bought earrings for Monica. Monica let Phoebe borrow them, who then let Rachel borrow them. Rachel lost one. Chandler asked Monica to wear them for a special dinner. During the whole episode, Rachel is looking for the lost earring. She and Phoebe finally come clean to Monica.
Monica puts on different earrings, Chandler looks at her and says how pretty the earrings look and on the way out, quietly thanks Ross (Monica's brother) for picking out such nice earrings. He had no clue they weren't the same earrings.