Does anyone know if it is possible to take a munged lvl file (like bes1.lvl) and literally "de-munge it", (turn it back into odf, msh, and req files)?
I'm asking about BF1 not BF2.
I don't think it is without substantial hacking knowledge
No, but for shipped maps and sides the files are already distributed with the mod tools. If you want to decompile a custom mod or map, it's not possible. You're better off contacting the original author and asking to borrow their assets.