According to the BIS-bible, they are "rubbing strips". Ooh, Matron!
Seems relatively easy to get them off. A screw from the cabin side of the door and a few plastic pegs. Though, depending on how tidy and hardy your car is, beware the plastic pegs. I've had similar attachments snap clean off on even 4 year old cars, so I'd expect them to be somewhat brittle on a classic.
Dan.