I took apart a disposable camera and found the flash capacitor inside.
4 (2) 0c
There are no other markings on it. What is this supposed to mean?
It means it is a capacitor that has been built specifically for that camera manufacturer, and was not intended for sale on the general component market. It therefore needed nothing more than some cryptic code that only meant anything to the manufacturer alone.
Typically open market photo flash capacitors have a voltage rating of 330v, and are in the 80uF to 120uF range. With a 'no label' component like this, you can assume it's going to be at the lower end of that range. Don't assume it's necessarily going to achieve that full voltage either.
The specification of an open market capacitor usually continues that when discharged into a 1 ohm load, they have a rated life of 5k flashes, which is more than adequate for a disposable, but of course nowhere near adequate for a flash gun or real camera.