No. There are two shims on each lever, which adjust the level of leverage applied to the brakes. With both shims in place you get direct ratio of travel between lever and brake. With both shims removed you get maximum 'servo-wave', which means that as you initially pull the lever it pulls a lot of cable to bring the brake shoes close to the rim and as the brake shoes engage with the rim, the lever pulls less cable per distance the lever is pulled, thereby giving more leverage. The benefit is more power and greater modulation of the braking power.
I found that for a front brake one shim removed (so intermediate between direct pull and full servo-wave) gave the ideal feel to the brakes. For the rear I left both in place. For some too much 'servo-wave' makes the brakes feel spongy - others can comment on this. I particularly like it because it makes 1-finger braking really easy, with good modulation.
My XT disc brakes have a modern version of 'servo-wave' in the lever, which works by the same principal, and I like it. I understand the current XTR disc levers do not have this.
I will try and see if I can find the missing shim in my toolbox, but I don't hold much hope, but either way it doesn't affect function, only that you are stuck with some servo-wave in the right lever.
cheers