Before filming started in New York, New Yorkers got this news.

Here are Rose Pelswick's exact words from Hearst newspapers on June 9, 1965. I alluded to them in the thread about the Blu-ray release.

I suspect location filming in New York hadn't started yet when New Yorkers read this, but I could be wrong. Microfilmed issues of Variety might confirm the time frame.

Consider that Hearst had been publishing Ms. Pelswick's reviews since the 1930s. She totally loved Young Mr. Lincoln with Henry Fonda. Her exact words from June 9, 1965:

Rock Hudson considers his newest picture. "Seconds,"
one of the most important in his career. He insisted
on a three-week rehearsal period before any member of the
cast stepped before a camera. Those who've read the script
say it's "as off-beat as 'The Manchurian Candidate.'" Well,
one would hope it will turn out to be far more off-beat. "The
Manchurian Candidate" was a routine melodrama with the
plot telegraphed as neatly as if it had been sent by Western
Union.