Yeah, that is about what I was expecting. Fox would wonder what is going on with Oscar's aura feeling like two auras mixed up like that and as he does know Ozpin's aura he'd recognize who is came from very quickly.

It is also said that Ozpin appears to know just about everything that goes on in the school, so I do imagine that Ozpin is aware of Fox's skills when it comes to aura-sensing (considering his are actually some of the stronger aura-sensory skills laid out by canon so far)?