Well, it's a usual sticker, less than 0.5mm thick, but pretty strong and stiff. It's easy to take off, but it can warp a bit.
However, because of its stiffness, it's almost impossible to glue it back exactly as it was
The edges will not stick strong enough. I'll have to use some glue and think of some way to press it while the glue dries.
Also, it turned out the edge at the side of the large pushbutton is removable and will fall out when the sticker is removed.
I think Lenovo has totally over-engineered this. Wouldn't it be easier to add one more screw at the bottom or the back, as on 4338, instead of adding this sticker and a separate plastic piece...