There are two varieties of 1828/7 half eagle, struck from the same obverse die but different reverses. The BD-1 is among the rarest of all half eagles of this type, but is only the second rarest 1828/7. On this overdate, being the among the rarest varieties of all U.S. gold coins, the 7 is clearly visible underneath the final 8 of the date. Records indicate that there are fewer than a dozen known examples. The Smithsonian's example doesn't even reach a Mint State grade, coming in at AU-58.

The example to the left was sold by Stack's Bowers Galleries in the D. Brent Pogue Part IV Auction, where it realized $282,000.