It looks to me like it's a mistake and should be 'of' (the name of the slinky).

for your specific context it should be "on" the slinky. Slinky is a trade name for many different things ranging from "slinky dresses" that were once popular to "slinky dogs" in cult films. So it "The New York Times" published an obituary for the person who thought of the name on "a slinky" whichever slinky we are talking about. Yes it means the person who came up with the name "slinky". Therefore it is not a mistake, although usually we say "the name of" but not in this case.context/scenario.