Every 454 TBI that i have seen has no Knock Sensor.
Not sure about you getting knock counts but i suspect that since the ECM is the same regardless of weather or not you have a KS installed from the factory, it would make sense that you are getting counts.
Keep in mind that on a truck that has a KS installed, you can put in a 3.9K Ohm resistor, and it will fool the ECM into thinking that everything is fine. With that setup you would still get knock counts, they would vary, but always remain inside the "normal" envelope.