Ok, I bought a 99' v6 Camaro I keep getting two codes P0420 and P0420(pending), catalyst efficiency low. I got this after one drive after resetting the computer. I looked though the monitors and this is what I found:

"Monitors are ready.
Misfire Ok
Fuel System Ok
Comp Com Ok
Catalyst Ok
Heated Cat N/A
EVAP System No
2nd Air system N/A
A/C N/A
O2 Sensor Ok
O2S Heater No
EGR system Ok"

I'm confused, it says "Catalyst Ok" but pops a P0420 code, but says no to EVAP and O2S. Does a "No" mean the monitor is not ready or it failed? Does N/A mean it's not ready or it doesn't have it or....?

I'm trying to learn something here so don't flame me for asking. I'm also open to suggesting on how to fix/what do do next. Cats are expensive so I'd rather do just about anything before that.

Needs a cat.
N/A means its not on the car.
No means its not done with the drive cycle for that system. Evap has a really long drive cycle that has to have a multitude of parameters met.