How to check the disc drive is the original?

You can’t really do anything else other than check the make/model number of the disc drive to see if it matches the type of drive that should be in your console. To check this, grab the model number from the console and Google the type of drive it takes. It should tell you, and you would look on your actual disc drive to see if the model numbers match. Now if they did a PCB swap, there really isn’t a way to tell and model number matching the PCB with the disc drive isn’t very helpful if the previous owner swapped the drive. If they did a complete drive swap, there is no possible way to get your console working without the help of Microsoft. It comes down to a DVD key mismatch at that point, and since the Xbox One has not been exploited in any way, there is no way to check if you have the original PCB and or flash a new DVD key to the PCB to match the the drive and console again.