So, as far as getting a NEW replacement part (Side Bezel) probably not going to happen.
Cosmetic components, and or case, bezels, covers, latches, etc etc....are not manufactured as spare parts...Unfortunately.
You would think every part has its corresponding SPARE, that is oderable.
But, unfortunately, in the world of computers.....many times a computer will only be produced for a few months to a year. Then a newer model using completely different parts and pieces will come out. So, spare parts (excluding circuitry) are just not made for spare usage.
Therefore you would have to do your best to (as you mentioned) find a PARTS (broken, non-working) only replacement computer. And salvage the parts you need.
Thats the world of IT for you.
I wish there were a better way.....but alas....there is not.
I knwo some guys that had to actually MILL out their own custom pieces, as their computers were so old...not even broken computers could be found.