idiot question regarding wheel bearings

[Glinko]

I've been thinking about repacking the wheel bearings on my 82 240d. I was thumbing through my hayne's manual to make sure the task wouldn't be too arduous when suddenly I become confused.

The manual specifies that there is a bearing seal on the wheel hub that I must "deform with a screwdriver and then pry off." There is a photo of the step mentioned, showing a man bending the crap out of some kind of ring-shaped object in the hub and then prying it off with a flathead screwdriver.

So I'm curious, is the bearing seal something that I have to purchase and replace, or is it something that can be left off once it's removed, or what?

PS - I'm a moron who knows nothing about cars.