I dont recall it looks like, but you might be able to answer your own qustion.

1) I would not add a 2nd woofer into the system while leaving the 1st woofer setup with the 2 serious flaws it has.

2) as an example, the "KM" series enclosure needs to be small and air tight. any leaks and its performance will fall off.

3) the "KMF" does not want a small enclosure/air space/cavity. However, the large space does not need to be air tight sealed. What is does need, is to have 100% front cone to rear cone isolation. You need a solid wall/cavity structure to prevent the air coming off the rear of the cone to mix with the air coming off the front of thee cone.

If you location you speak of, offers #3, then you could go with an FA woofer. An example of this would be a Nautique G boat. Free-air woofers in the port locker and helm cavity. If said location is small and sealed (or could be sealed with a little fiberglass or marine caulk work like ive done on a Tige ASR), you could use a non FA woofer.

Now the final challenge. Anytime you place a woofer in a closed locker, you rob some performance. So ideally, you would want to put in a vent to let the bass radiate out.