Sunroof cable replacement questions

I'm in the process of replacing the sunroof cables on an '86 Carerra and have two easy questions for those of you that have tackled this before.

I understand that the updated cables (964 part numbers) will work with the old guides if you modify them. It seems that if you file some material off of the bottom of the 'shoe' on the side opposite the cable the dimensions will be the same as the old cables. Stoddard lists a plastic slider (part number 964.564.241.00) that their catalog says was part of the original cable, but must be purchased separately now. On my old cables, I don't see anything like a plastic slider. Do I need these additional parts?

Also, the Bentley manual says to put the cables in without any grease on them, but my old ones had a significant amount of a light amber grease all over. Am I supposed to put grease on them as I reassemble the cables into the guides?

TIA,

Chris.