MountainXBGL actually has a point. The differences are all over the design, not just with the AM.
Pull out any cent from 1990-1992 and compare it with any cent from 1993-1997 and you'll have your examples of the two different reverses. Don't only look at the AM, but look also at the spacing of the letters in STATES, the designer's initials, the steps of the building...you'll see big differences in all those areas. This is not just a case of die polishing making the letters split apart, it is actually two completely different yet very similar designs.
In the case above, you're just looking too hard for a split. Get a 1990-1992 cent and compare this one with the older one you pull out. You should immediately see that this coin isn't a
Wide AM.