I am sure that GS did not forget to install lifts. I know I would not trust lifts if I was working on the engine lying into the access.
I believe they did not install them on purpose because of this reason. I know the CAT Dealer was impressed that I had made the wood supports when they had to change the injectors on our engine. If anything, GS should make a solid support to use to hold the mattress base frame up. I found it much easier to remove the mattress and set it at the rear of the coach, really makes the matress base much easier to lift and hold in position and I feel much better with less weight being above me or the person working on the engine.
Also, I use my rechargable drill/driver to remove/install all the screws. I can actually have the access open to work on the engine in about 5 minutes after I figured everything out the first time. I keep the wood support stored under the bed.
Ron