There is no doubting that a great number of collectors continue to search through rolls of Presidential Dollars looking for error coins. Take, for example, this evidence: the coins were released on February 14, 2008, and NGC has already received a handful of submissions of error coins. While the earliest issues of the series were found without edge lettering, the more recent issues do not exhibit this error in abundance (if at all).
Instead, NGC is seeing different sorts of errors, which are as a general rule much more scarce. For example, NGC has certified a few James Monroe $1 edge lettered planchets. These are coin blanks (technically planchets), prepped for minting, that were never struck but passed through the edge lettering machine only. Depending on the settings of the edge lettering maching, this can result in a few possible outcomes, the most desirable of which is a "blank coin" showing full edge lettering.
If they’re not struck, how do we know that these coins are James Monroe dollars? Simple. The date 2008 appears as part of the edge lettering, and these coins were released early in the year. The next coin in the series that will be dated 2008 is the John Quincy Adams, and that coin is scheduled for release on May 15. Until that coin is released, NGC can designate 2008 edge lettered dollar planchets as (JAMES MONROE). After the release of the John Quincy Adams dollars, edge lettered planchets dated 2008 will not be attributed by President at NGC. Thus, only the first coin issued each year is eligible for such attribution.
Edge lettered planchets essentially come in two varieties, fully edge lettered and partially edge lettered. Edge lettering is weak on all edge lettered planchets because they have not been struck to their full diameter (as constrained by the collar). After upsetting, the planchets are fractionally smaller in diameter than their final struck dimensions. Because of their smaller size, the edge lettering is applied under less pressure and can be weak. This may also cause the edge lettering to be only partial. Alternatively, a planchet can get hung-up in the edge lettering machine, and only partial lettering may be imparted. This type of partial edge lettering has been seen on a number of struck Presidential $1 Coins.
In addition to the errors described above, NGC has also certified a Monroe $1 Coin missing clad layer. Presidential dollars are composed of the same three-part clad layers as the Sacagawea dollars. Planchets missing an outer layer show one side in rich copper color, as the pure copper center of the coin is exposed. This bright red is a sharp contrast to the "golden" appearance on the other side of the coin, adding to the drama of this error. Because coins missing a clad layer are thinner than normal planchets, they show weakness in the design especially along the edge of the coin.