Yes, it is possible to have only oil leaking if the break is limited to an oil journal/track. The gasket is the seal/barrier between the cylinders and the oil and coolant "tunnels" that run between the top and bottom sections of the engine, so it's likely that, sooner or later, oil and coolant are going to get together. You should take care of that.

While the head is off . . . have you changed out the timing chain/tensioners yet?