"is the shell a cyberlimb".
I think you missed my point...
Limbs = arms and legs
Cyberlimbs = not only arms and legs but also torso and skull.
Whenever they use the word "Limbs" then, with a strict reading, they only talk about "arms and legs".
If they use the word "cyberlimbs" then they not only talk about "arms and legs but also torso and skull".
"take the average value of all limbs involved in the task." = arms and legs
"If a task requires the careful coordination of several limbs, use the value of the weakest limb." = arms and legs
"Cyberlimbs cannot hold any bioware, nor any cyber-implants that take up Essence rather than Capacity." = arms, legs, torso and skull
"Essence cost, Capacity, and other stats can be found on the Cyberlimb table." = arms, legs, torso and skull
"Cyberlimbs have other useful features." = arms, legs, torso and skull
"They give you 1 extra damage box on your Physical Condition Monitor for each cyberlimb you possess" = arms, legs, torso and skull
"Cyberlimbs can be dangerous even if they don’t have cyberweapons installed— their unarmed Damage Value is (STR)P." = arms, legs, torso and skull