I replaced my battery a couple months ago, while checking fluids recently, I noticed that the neg. clamp was loose, so I tried to tightin it up but it was already as tight as it would go. I bought some more clamps like this one except not brass and the plastic covers that were on the battery dont fit, so I went back to the store and bought some more of those flat metal ones except these have the lugs that you crimp onto the cables and than screw onto the clamp itself with a wing nut but the plastic covers fit. I dont like this set up and was wondering if the plastic covers were necassary or should I just go out and change the cables? I am not a big fan of that thin metal trash that never fits right on the battery posts so thats why I was asking about the covers, I also have no problem changing the cables completely if those plastic covers are necassary. Corrosion is no problem, I spray di electric junk of every electrical connection anyway.

 

The plastic covers are not really necessary. just cover the posts if you are working on the truck with the hood open so you don't accidentally put a wrench across it.
The first battery lug you linked is a poor choice because the strands will corrode under the clamp part and you'll have problems. i would get a type that solders or crimps on or just replace the cable.

 

When looking for replacements, keep in mind that the battery posts are not the same size. The negative post is smaller, so if you try and use a clamp designed for a positive post on the negative post, it's gonna be loose.