There's a lot of action in the Flatiron/NoMad area, but one building that has been quiet is 323 Park Avenue South, one of the last projects by Charles Gwathmey. We swung by earlier this week, and construction on the 10-story building is nearly complete. Workers were finishing up things near the entrance, but the scaffolding is gone?as are most of the units. StreetEasy shows 12 of the 17 units to be in contract, including the $8.25 million penthouse. There's just one active listing, a 1,371-square-foot 2BR/2.5BA listed for $2.45 million.