There’s pretty good evidence suggesting “five golden rings” isn’t jewelry but instead a reference to either the yellowish rings around a pheasant’s neck or to “goldspinks,” an old name for a pretty little bird called the goldfinch.
Not only that, there's reason to believe that every verse in this 18th century carrol is about a bird. Specifically, birds eaten at medieval feasts. Though some of the verses are harder to decode than others.