What happends when sending SIGKILL to a Zombie Process in Linux?

In Linux, when a child process terminates and it's parent has not yet waited on it, it becomes a zombie process. The child's exit code is stored in the pid descriptor. If a SIGKILL is sent to the child, there is not supposed to be any effect. Does this mean that the exit code will not be modified by the SIGKILL or will the exit code be modified to indicate that the child exited because it received a SIGKILL?