[Kos-Mos]

meh.

You can install that stock on an ICS Rifle.

The split mechbox has nothing to with with it.

If you remove the screw inside the buffer tube of the ICS stock, you can remove the part that goes on the back of the receiver.

The only reason why it will be harder to fit is that you have to modify that part with a dremell tool, a file or sanding paper.

The rear part is made tapeded in two directions. First you will have to sand/grind in width the two prongs on the stock adapter.
Then you also will have to remove some material on both top and bottom faces of the same two prongs.

It's not hard to do but you have to understand. Worst case, you won't be able to fit the stock tube all the way against the receiver, but it will work. You HAVE to use the ICS stock screw (unless you have a full stock. The special battery connector one is a CRANE stock) because it shorter and screws into the part you have to modify instead of the mechbox.

Take everything from the rear of the receiver appart and you should understand.