Yes, according to "Diesel Locomotives of the New York Central" by Edson, Vail & Smith, the RS-11s in all-black (but with the script herald) were built in June 1957. It appears that engines built after that, like the GP-20s of 1961, were delivered in the 'cigar band' scheme.
I think Victor has it pretty close. I have a photo of one of the first cars to roll out of the Despatch Shops in Century Green with the new simplified "Cigar Band" oval in July, 1959.
Central began "economizing" on their locomotive paint schemes in 1957 when an order of Alco RS11 road switchers arrived in solid black but these had the short-lived "Script" herald.
Like any changes on a railroad the size of NYC, these repaintings took many years to be fully adopted and there were still some two-toned gray E-7s I remember seeing with a Penn-Central hearald quickly "patched" on the nose door and one of the side panels.
Have Fun, Ed
For some reason the date 1959 comes to mind, but I stand to be corrected. That was about the time the the railroad was making major changes instituted by Perlman I believe. I would recommend joining this group and asking, as I'm sure someone there would know for sure:
https://groups.yahoo.com/neo/groups/NYC-Railroad/conversations/messages
Victor A. Baird
Fort Wayne, Indiana
When did the NYC introduce the cigar band scheme, specifically on F7s? Any delivered in this scheme, or repaints?
Thx