Ron Guth:
1839 Seated Liberty Half Dollars come in two variations: Wiith Drapery and Without Drapery, referring to the fold of drapery (or lack thereof) beneath Liberty's left arm (viewer's right). The earliest version of the 1839 Seated Liberty Half Dollar match the 1838's in that there is no drapery below Liberty's elbow. Later in 1839, engravers added drapery to balance out the dessign. Subsequent to this change, and "No Drapery" varieties are unintentional and were caused when over-zealous polishing removed the drapery from the die, either partially or fully.
Across all grades, the 1839 Drapery Half Dollar is slightly less common than the No Drapery inb