I'm new to the forum so give me a little leeway.
I found the forum because I am trying to track down a misfire,but the check engine light isn't on and I have no stored codes.Therefore I have read many posts on the coils and plugs and intend to replace them all myself when the weather in the Northeast warms up.
I bought my'01LS used,while still under warranty in '04 a dealer replaced both valve covers and seals because of leaking oil that was smoking.

Here's the point of my post. The Dealer said that the new valve covers were a redesigned version and that the problems with leaks and coils would be cured.
The part numbers were XW4Z*6582*BB and W4Z*6582*AB.
Are these in fact a improved design? Wouldn't that constitute kind of an admission on the part of Lincoln that the original design was faulty??

It was the gaskets that were redesigned, not the actual covers themselves. Since it's Ford, it's not an admission of anything, as they don't warranty the 00-02 coils, gaskets, etc. like they do the early model 03s for 10 years/100,000 miles.

You should be good on the gaskets; the coils though, you'll have to replace on your own. If you push your car hard enough, it should throw a CEL and tell you what cylinder you need to replace. Or you can do them all and save yourself the headache of replacing one at a time until you get all the weak ones replaced. Might be worth it... might not...