Yes, more then likely your Toyota Camry is running rich and leaving behind partially-spent fuel in the form of high CO. Replacing your Toyota Camry's oxygen sensors was a good first step (assuming they needed replacement), there are however other components which need to be inspected and if defective replaced as well.
The additional sensors which should be inspected for proper operation (and which also play a significant role in determining air/fuel ratio) are the Engine Coolant Temperature (ECT) sensor and the Mass Air Flow (MAF) sensor. If your Camry's coolant temperature sensor is not operating properly (not sending the correct voltage signal to the Engine Control Module) the ECM will not be able to properly calculate how much fuel to deliver to the combustion chambers. When the engine is cold the ECM is programmed to deliver a richer fuel mixture (more fuel). As the engine warms up, the ECM will lean out the mixture. Insuring the ECT is sending the correct voltage to the ECM is important for correct air/fuel ratio (optimum is 14:7).
Your Toyota's MAF sensor measures the amount of air entering the intake manifold. This sensor must send accurate information to the ECM as well in order for the ECM to calculate exactly how much fuel to add to the air entering the combustion chambers.
What a smog check repair station will do during their diagnosis is conduct a Fuel Feedback Test. A fuel injection "feedback" test will inspect all your vehicle's emission control sensors. It will ensure the oxygen sensors are working properly, your Toyota Camry's emissions computer is receiving the signals from the oxygen sensor (as well as other emission sensors), the computer is computing the data properly and sending the correct signals to the fuel injectors to either increase or decrease fuel delivery to the combustion chambers.
