there's no way to know
I'd be surprised if the original Freon (R-12) was in it.  How long have you had the car?  Have you ever had it recharged?
It might be simpler to indicate HC-134a is in the system.  You can recharge with it, nowadays no one still believes the hoses and seals have to be changed out.  R-12 is _very_ expensive... HC-134a isn't as expensive, but it isn't cheap either.