On mssqltips.com you can find my post Exporting CLR Assemblies from SQL Server back to .dll files.

This post describes how you can export the assemblies from SQL server back to physical .dll files. This can be very useful in cases when you do not have the source code for he assemblies inside the DB and you would like to do a security review of the assembly. This commonly happens if you receive the assembly as BYTE code in T-SQL.