The O-rings will help if bottoming out the keycap is producing undesirable sound. However, gently tap the edge of the spacebar and see if you are hearing a rattle/wobble sound. If you are I don't know that there is much you can do to correct this, unless somebody knows of a mod or trick.
By the way lubing this is pretty easy- just pop the keycap off and you can access the stabilizer with a wooden applicator. Disassembly is not required. Also try pushing down on the entire keycap firmly and evenly. If the stem is not pushed inside the cap all the way you will get additional wobble.