They actually had rings.
They were just some silly, flimsy bands Sam had gotten at the fair during the summer before their senior year. Maybe he won them, maybe he found them in some kind of packed food, Kurt wasn't sure. By the time he got them, Sam was already pretty drunk: he was incredibly proud of himself for getting them, and tried to serenade Kurt with some Enrique Iglesias while putting the ring on Kurt's finger (also suggesting that Kurt show him the Single Lady's dance sans clothes) and his kisses tasted a little like beer and a little like orange juice.
Sam believed that the evening was totally worth it, even if he gotten thrown in a dumpster the next day on his way home from work; the whole thing had happened soon after he came out, and the atmosphere in football team was still pretty tense. Kurt, incredibly moved and worried by how much Sam would go through for their love, suggested that maybe they get something engraved on them to give them even more meaning – he had Breakfast at Tiffany's on his mind. After watching the movie (Or rewatching it, in Kurt's case) they both agreed that this idea was pretty romantic, though cheesy (and plagiarized), and after putting each other's initials on these bands, they never actually took the rings off.
It wasn't like they flaunted their relationship or anything, because getting extra attention was the last thing they wanted in a place like Lima, which was still getting used to out and proud gay couples. No one seemed to pay much attention to the rings anyway; there were some rumors at school, but they didn't care. Only Rachel and Quinn had talked about them openly, Quinn by embarrassing Sam and reminding him of how he proposed to her before, and Rachel by talking about them way too loud and freaking out Finn. ("Dude, what the hell? You can have at least let me know you were getting married, or, you know, made me your best man or something!")
So when they exchanged these rings for real, gold ones, it felt a little strange. They didn't feel like throwing away the old rings, though. So they kept them.
