Yes he is. If you look at his avatar, his shirt says staff. Not all of them wear the staff shirts but thats normally a good clue that they are staff. If not you might have to ask them but in general if they show up getting skills/"exploring" while the test is closed then they are staff/devs.
wow my observation skills suck i did not see that t-shirt XD, either way tho i kinda figured he was staff since there's no other way for him to be getting skills right now