The Shift Boot on our 80 240 didn`t sink down like yours. it stool up tall. was the original one, and had seen better days.
I looked here in pelican for Shift boots, but they don`t list the MB one. I did see a thread I started on Shift boots.
http://www.peachparts.com/shopforum/diesel-discussion/342420-leather-shift-boot.html
I found a Leather Boot on a Saab Convertible with a 5-spd. I found a few more since. They were all on a 2 door Convertible.
I have the plastic piece around the shifter, and did a slight mod to it. cut 4 little notches, 2 on each side for the plastic ring that to boot fit too.
I did order a rubber MB Shift Boot, but it was like a piece of Tupperware when it was cold. Think it was made in India.
Charlie