I use polyurethane dust covers on all my ball joints and tie rods. I just put one on a lower ball joint on my 300D, after forcing grease in. It looked OK, with <10 mil play, just dry grease and slight surface rust. I found the right-side ball joint too worn, with no boot left, nor grease. Why I am on here searching. I do have a shop press, once I get the part. If a cheap rubber boot, I will install a poly one. I had a bag of Energy Suspension 5.13102R dust covers for my old Chryslers that fit well.