Is Grand Army Plaza Landmarked?

We were playing around with Citymap this evening and noticed something odd.

Is Grand Army Plaza, Brooklyn's grandest public space, a designated landmark?

In Citymap one can select additional options to show historic districts, individual landmarks, scenic landmarks, and interior landmarks. We checked every landmark option there is, and result is shown above. Historic districts (Park Slope to the left; Prospect Heights above) are shown in brown. Scenic landmarks (Prospect Park below; Eastern Parkway to the right) are shown in purple. The Soldiers and Sailors Arch in the middle of Grand Army Plaza is shown as an individual landmark.

But the rest of Grand Army Plaza appears to be unprotected by any kind of landmark designation, which seems an odd oversight. We had always assumed that the GAP berms etc. were protected under Prospect Park's scenic landmark designation. Are we wrong?

In fact this page at the city's Dept. of Parks and Recreation states that the Plaza itself is indeed a landmark and was designated in 1975:

The bust of John F. Kennedy was added in 1965. In 1973 the Arch was designated an official City landmark, and in 1975 the entire Grand Army Plaza was designated such as well.

If this is true, then why doesn't the GAP oval appear in purple on the map above? Or is this just an artifact of the mapping system?

UPDATED: We tracked down Prospect Park's original Designation Report from 1975, and it appears to include Grand Army Plaza after all. So Citymap's omission of GAP from the Prospect Park scenic landmark appears to be a mistake.