Well, what we do know is that it was definitely no later than when Sam left (in SR 1482, which I think is FA 60), because in The Tale of Years it says
Quote:
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Originally Posted by Tale of Years, SR 1482
Among them the tradition is handed down from Elanor that Samwise passed the Towers, and went to the Grey havens, and passed over Sea, last of the Ring-bearers
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Which means that at the very latest Cirdan left with him then, but definitely no later.