How do I know if my t/o guide tube is worn?

[chrisp]

It's an expensive part so I don't want to replace unless I have to. It has some surface wear but only in one area. The plating is clearly worn and there even a little edge wear there is some wear into the tube. Otherwise it's perfectly round and the rest of the tube looks brand new.

Should I just rotate it 180 degrees when I install it so there's a fresh surface at the contact point? This may be tough to figure out because I do not recall which orientation it was in when I took it off because it was greasy and didn't see the wear until I cleaned it. Would you expect the wear to show on the top or on the bottom? Anyone have any experience with this?

Thanks.