And the answer is yes, per my FB chat with Sonja at TSA, you do need to complete the declaration (Form 6059B).
You'll make one one stop at the Customs booth and hand your declaration form to the CBP officer.
O’Hare International Airport now offers expedited “1-Stop” customs processing for international passengers arriving without checked baggage. The new initiative will streamline the U.S. entry process and minimize customs wait times.
Who Can Use It?
“One-Stop” is available to all passengers who arrive at O’Hare’s Terminal 5 with only carry-on luggage, no checked luggage and proper documentation.
Where Do I Go?
“1-Stop” informational signage in seven languages is posted in the corridor leading to the U.S. Customs and Border Protection (CBP) passport control area. The signage guides eligible travelers to enter designated lanes for customs processing.
Travelers will make “one-stop” at a booth with a CBP officer, then move on to an “express corridor” that bypasses baggage claim and CBP Exit Control inspection areas.