Quick Sega Saturn game case question

[MortalMonday]

I just snagged my first ever Sega Saturn system. I'm thinking of buying Panzer Dragoon Saga. There's a listing for a copy right now with mint discs but banged up game case. It has scuffs, scratches, and a crack along the spine too. Do you think it would be easy to replace the bad game case with a fresher case. Now Saga comes with 4 discs I believe, so I'm not sure if that would make it harder to find an appropriate replacement case. Maybe I can just put the interior guts of the bad case (the parts that hold all the discs), inside a replacemt case? Is that possible? I've never even held a Saturn game case, that's why I ask.

Also anyone know what the battery inside the system is all about?