There are two options how you could make use of a signed module:
- compile a public key into the kernel so the module signed with a private key can be checked against it (requires kernel rebuild)
- enable secure boot so the module signed with a private key can be checked against a key held in the computer's NVRAM
IBM x3650 m2 build in 2009
module is distributed not as kernel object file but as a source code, therefore you have to sign the module by yourself, because signing a source code does not make sense. Moreover, since every kernel update requires the module to be rebuilt that means that the module signature has to be updated every time you upgrade the kernel.
Please don't hesitate to ask for directions, should you need any assistance with module signing.