I am here crisgal.
It would appear from your post that you have aquired an already-played model for your (seriously lucky - do you want to b my mum!!!) son.
My suggeestion would be to enquire with your local guitar emporium, and quote them the exact measurements, and see what they can advise.
You will probably struggle to get an exact fitting case that is not branded, so it may mean buying a larger case and getting a little modification to fit the Schecter in safely.
Again, your local guitar shop may be able to assist, and if not, most of them have contacts with local luthiers, and it should be quick and inexpensive to have some modifications made.
It is worth it - a well-protected instrument looks better, sounds better, and keeps its resale value.
Hope this helps - if you need any more advice, please re-post and I will contact my experts in this field for some names and contact details for you.