Most of the 1861 $2.50 Gold coins you will come across feature what is called the "new reverse." In 1859 the reverse dies on the $2.50 Gold Liberties were changed slightly. Most of the coins struck between 1859 and 1861 were struck using this new reverse die. However, a small number of coins were struck using the old reverse dies. Hence the name "Old Reverse."
Experts at PCGS estimate that there are less than 100 surviving examples of the 1861 $2.50 with the Old Reverse in all grades. Although PCGS population reports show that PCGS has certified 88 coins in all grades, many believe this number is slightly inflated due to resubmissions.
Interestingly, PCGS scores this coin as an 8.0 on the PCGS Numismatic Rarity Scale. The Rarity Scale converts the survival estimate for a particular coin into a number from 1 to 10 (with decimals). The higher the number, the rarer the coin. A score of 8.0 on this scale is incredibly high especially for a coin at this price point. As a comparison, the famed 1911-D $2.50 Gold Indian scores just 3.4 on this same scale.
This particular example is 1 of just 12 coins PCGS has graded Choice About Uncirculated AU-55. As you can see this is also one of the nicest AU55 examples you can find. This coin has the look of an AU 58+ as it still has a lot of original mint luster.
When we came across this coin, we knew we had to have it. We know how rare it is just to be offered an Old Reverse $2.50. Notably, the only one struck during the Civil War. Who knows when the next time we will see another one again?