take this advice with caution! And
take an imagebackup (ghost, clonezilla) of your drive(s) before you begin doing something with them
I am assuming that the nas device was using some sort of linux and using mdadm as raid manager.
If that was the case (and only then) you can try the following:
Connect both devices to your computer and run the following code after booting.
sudo mdadmin --assemble --scan
to find any array configured on the drive and try and assemble it.
would give you information on the state of the array.
As I said, please be very
cautious with that if the data on the array is in any way important to you.
You could also try and take backup images with dd and try your magic on those, thus leaving the original discs untouched in case you would later like to let some specialized company try it.