That is a tough question to answer. There is software that will identify hardware, such as CPU-z or GPU-z, however the firmware on the hardware can be worked on, to make the hardware seem to be something else (See: Vamery GPUs).
The best way to check components is to visually inspect them along with software identification.
A picture of the motherboard, with the BIOS information will be able to identify it. GPU-Z and a picture can be used to identify. The DVD writer should just be visually inspected, just look at the stickers on it.