Just wanted to provide an information update for fellow New Yorkers in particular; based on further research the Bowling Green location apparently does not accept walk-ins for changing passport details/LPR to citizen type changes. Am not totally surprised as it is a somewhat particular office based on what I have read. Maybe one could try one's luck there but it seems unlikely.

Accordingly I went to JFK T4 to get this done. There is no reception desk at this GE Enrollment Center, just a sheet of paper where you sign-in. There were tons of people with appointments waiting, some almost an hour past their appointment time. After waiting a few minutes, I had to ask one of the CBP officers when he came out into the waiting area directly, and thankfully he was kind enough to take my passport and GE card and make the change from LPR to citizen in about 3 minutes.

I signed on to the TTP website tonight and saw that my GC was duly removed, and there is a gold flag next to my American passport so hopefully all will go well next time I come through.