When a die was used beyond a normal lifetime (seems more common in the early 60s) the die spreads outwards ( some flattening) and the lettering gets closer to the rim. Also sometimes in dryer coins, the rim comes closer to the center (PMD), That is why I would like to see the reverse also along with CPM9ball. In the first case, maybe the reverse was changed out earlier and be sharp on the coin, in the dryer coin, there should be similar effect on both sides.