[Iarhen]

I don’t think that Saruman knew about Gandalf’s ring. If he had, then he would have taken it from Gandalf right away, since he knew the connection that the 3 had with the One, feeling the power of the One whenever someone wore it. He could also, with the aid of Narya, know who the bearers of Vilya and Nenya were (and probably he would try to seize them from Galadriel and Elrond, knowing the terrible amount of power he could have with the 3 Rings on his hand… and the attack on Rohan would have been diverted towards Lórien and Rivendell).

And second, and most importantly, if Saruman knew about who the 3 bearers were, Sauron would have gotten the information when he “spoke” with Saruman through the palantír.

And I think the story would be a lot different in the end…