WAM is not an error and if the OP is referring to LIBERTY, I'd say it is a plating issue as this is a crappy Zincoln, but that's just my opinion.
Variety. Not an error. But still fun. I've had much more luck finding 2000 WAMS (100+) than 1998s (~80) and 1999s (2). Each time I find one though, it's like finding a little treasure
Bottom one on the list. Nice find 1. 1992 Close AM - extremely rare 2. 1992 D Close AM 3. 1998 S Close AM 4. 1999 S Close AM 5. 1999 Wide AM 6. 1998 Wide AM 7. 2000 Wide AM - least rare
Finding the 1999 WAM is a difficult task. Aside from one CRH enthusiast who was close to the release point for this variety, and who had found several of them, the most I've heard from CRH is 2 or 3.
I have come across a few of 2000 WAM's from CRH, but only a handful. It is still exciting when you do find one, even if it is the least rare, so congrats on this find!
I don't bother looking for errors on Zincoln's there are to many anomalies that mean nothing and have no value. Cool but not worth saving in my opinion.