This is incorrect, a schematic only shows what electronics should contain. It doesn't provide any proof of what hardware actually contains. For that the best way to verify is to visually look at the hardware, we made OnlyKey hardware easy to verify with a clear transparent coating. When you look at OnlyKey you will see one Freescale K20 MCU, you can read the manufacturer number on it and know exactly what is in your key.
The microcontroller isn't the only thing that matters in your design. For example, since you're dependant on the ADC for seeding the RNG, it'd be nice to know what is connected to those pins, which a schematic would reveal. I can't tell that just by looking through your clear epoxy.
Even if I did drill holes in the casing and probe components, I have no way of knowing if what I'm seeing is expected or not without a schematic.