Given that's what you were talking about, you should definitely have them installed.
My car is native to a low rust region, but one of those guards was missing when I got it. On that side, the engine cradle had numerous pinpoints of surface rust, apparently caused by rock chips. The other side, with the wheel liner still installed, was pristine. Those liners are definitely important, even though they're a pain to remove.
Just noticed that Dickman doesn't have pre-88 liners anymore. That sucks.. I'm using an incorrect year liner myself. Basically works but it's not quite right.
[This message has been edited by armos (edited 02-10-2014).]