If a non-Jew does an act which would be considered a kiddush Hashem or chillul Hashem if done by a Jew, does it have the same status?
Kiddush/chillul Hashem taken to mean showing the world that this is how Hashem's chosen people behaves:
No, by definition: The gentile cannot be representative of a group he does not belong to.
Kiddush/chillul Hashem taken to mean letting one self be killed rather than doing something for which one is required to let oneself be killed rather than doing:
Yes, by definition (at least theoretically): If that is the label of an act, and he did that act, then it has that label.* (However, as per Sanhedrin 74b, there may not be any actions requiring a gentile to sacrifice his life, rendering occurrence impossible.)
* My head spins from reading my own words!