That is hard to tell since different manufacturers use different styles of remote gain controls... but as long as it looks like a phone jack.. i say all the power to you to check...
I'd like to know this as well. I bought a used kicker w/o the remote bass control, but I'm not really worried. From what i figure from looking at my friends kicker as well, its' seperate. It's the volume control for whatever you have set at your amp, allowing less, but not more than what you have set at the amp.