Parking brake cable question

[wpavlis]

So I am redoing the rear brakes on my 68 c10. I have two questions. On the intermediate cable there are these plastic guards where it passes through the frame. Does anyone know where I can get replacement ones or if they even matter? My second question is about installing it in the guide attaches to the rod on the passenger side. I got a new cablend from inline tube. The end is slightly larger than stock and I can't get it through the guide. Any ideas? I tried spreading it apart but thar didn't work. May need to file down the cable end or something. Thanks