they really just look worn (are they original ?), plus, if you've been having some misfires from the worn plugs, the A/F sensor (O2 sensor) may detect that as a rich condition, causing the ECU to pull fuel from the fuel trims.
Givene the state of those plugs and assuming you have no other moderate to major problems with the engine, I'd just monitor the car after the plug change for any issues. Unless you have a way to read the freezeframe data(some OBDII scanners can), it might be hard to know if some other system on the car is forcing the system lean.
and congrats on surviving that job!