He slowly puts on the ring when he asks "You didn't see me die.. did you?"
Can't be sure what ring this is, but the symbolic meaning is obvious: masonic ring, put on the masonic finger.
The whole scene suggesting that "his death" was faked by brothers in freemasonry.
Whoever "he" is. Is it a message from someone who "died" recently, like GHWB or noname?
Or maybe the cabal tried to get Spacey suicided? And it's a message to them?