In arch/x86/Kconfig of the kernel tree it says for CMDLINE:

	  Enter arguments here that should be compiled into the kernel
	  image and used at boot time.  If the boot loader provides a
	  command line at boot time, it is appended to this string to
	  form the full kernel command line, when the system boots.

	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
	  change this behavior.

	  In most cases, the command line (whether built-in or provided
	  by the boot loader) should specify the device for the root
	  file system.

and for CMDLINE_OVERRIDE:

	  Set this option to 'Y' to have the kernel ignore the boot loader
	  command line, and use ONLY the built-in command line.

	  This is used to work around broken boot loaders.  This should
	  be set to 'N' under normal conditions.

So both commandlines will probably be used. I don't think an initramfs will normally interfere with the kernel commandline. In any case you can make sure you got what you wanted with cat /proc/cmdline.