In the most general sense, no I don't think you should be -- the caveat being that I'm not really sure what it means to be "trans-race".
This isn't the first time I've seen something like what Mr Dolezal has done or said. I'd seen a comment like "I'm not white mentally" or something*, but it looked closer to either someone just having a joke or alternatively someone who was going through a particularly extreme phase of rebelling against the system. At any rate "trans-race" people are far, far rarer than transgender people.
*
http://i.imgur.com/D0AyeLL.png, with apologies for the language, if anyone's interested.