Spare Guibo that went unused for my 1987 635. I think it'll also fit 633 models but you should verify first. May fit other models as well. If I remember correctly, I installed it, but realized the old one was fine so pulled it back out, so it's essentially brand new but that was a few years ago hence the low price. As you can see in the pictures of both sides, it's clean with no cracks or other issues.
Buyer pays shipping from Austin, TX.