Not the corners for me, but the "feet" of the topcase digging into the palmrest, which would splinter the plastic, then you'd have holes in the case and jagged plastic splinters digging into your wrist as you typed, not enjoyable.
This: https://ismh.s3.amazonaws.com/2014-02-24-macbook-topcase.jpg is exactly what mine had, on both sides.
Shame because it was the last macbook that was really easy to upgrade: the battery was removable (with a simple lock), and behind it were the RAM and 2.5" drive slots.
The next generation was not that hard but you had to unscrew the entire bottom shell, and the battery was glued.
It was my first Apple laptop and I have fond memories of using it during my college years.
Did the same years later buying up first gen iPod Nano and trading them in for sixth gen because of the battery recall.