The LMT SOPMOD stock's cargo tubes can only be accessed if you remove the stock. This is because the point of the tear-drop shape hits the receiver extension tube, as shown with the right hand cap here.
Damage Ind. improved the design by adding a small tab opposite the point and a slot for it in the body of the stock. That lets you remove the cap with the stock installed.
Notice that you can still chose to place the caps in their original orientation if you're concerned about them coming out during use.
Win-Win I says.
I am finding that I am liking how this stock feels more and more.
Oooops, except for one little thing. With them in the original position, there's nothing retaining them front to back except tension from the o-ring. C'est la vie.