Most rubber products do have a thin skin on them from the molding process. Or in some cases there's a trace of the mold release on the surface. I know that motorcycle tires definetly need to be ridden gingerly and max lean angles approched with care. But this only takes a few moments of scrubbing to wear this layer or agent away.
On bicycle tires the same stuff is likely present. But if you don't encounter an emergency braking situation in the first mile of riding or lean into some turn at a crazy angle within that same first mile of the starting point you'll never notice that the "problem" went away on it's own from simply riding along and through your normal turns.
If you're talking about some internal carcase situation then I'd have to say no, there's no breakin required. Or at least anything that is stressed and lets go is a defect which will likely occur again within that first couple of miles.