Yes, the seat belts go through this trim panel. On the 77 240D I did 6 months ago, I did not remove the shelf. I had enough room to pull the cord from inside above the shelf. You won't need to remove it to address minor rust in the channel, unless you are really sloppy.

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)