Frodo sees Nenya on Galadriel's finger after looking into the Mirror of Galadriel, and yet Sam is unable to see it. Galadriel also says the following:
It is not permitted to speak of it, and Elrond could not do so. But it cannot be hidden from the Ring-bearer, and one who has seen the Eye. Verily it is in the land of Lorien upon the finger of Galadriel that one of the Three remains. This is Nenya, the Ring of Adamant, and I am its keeper.
So does this mean that Frodo would have been able to see both Vilya on Elrond's finger and Narya on Gandalf's finger? I am assuming that the Three are like the One in the sense that they must physically be worn in order to utilise their power. Or does the quote by Galadriel mean that literally only one who is Ring-bearer and one who has seen the Eye is able to see the other rings?
Of course, being able to simply see the rings does not imply he would necessarily know what they were, but clearly Sam was unable to see Galadriel's ring at all. Could Frodo see Narya and Vilya when in Rivendell?