The only place on the system that I am aware of that currently displays the "M Central" logo is the mezzanine at Mount Vernon West Station.

MTA Metro-North Railroad's 7th Heritage Unit Preps For Its Debut. On Thursday, June 19, 2025, P32AC-DM MTA Metro-North Railroad/MNCW 203 (Two-Tone M Central Heritage) displays the new paint scheme of the railroad's 7th heritage unit. Unlike the previous 6 heritage units, this unit was painted, and not wrapped. The design commemorates a pre-Metro-North scheme used by the MTA for seven FL9s that were rebuilt by Morrison Knudsen in the late 1970s, with the "Central" denoting their planned use on the former New York Central Line (Harlem & Hudson) in New York State. The unit is rumored to be making its public debut soon. It is seen here being turned to have the locomotive face south. Cameo appearances by MNCW 211 (New York Central) and Amtrak 100 (Midnight Blue/50th Ann).

YouTube Video: https://youtu.be/3iAQ10Elp2s

Full resolution pics and prints:
https://www.riverrailphoto.com/mncwworktrains
https://www.riverrailphoto.com/metro-north

More from the MTA - MNCW 203: https://www.mta.info/press-release/photos-metro-north-railroad-unveils-seventh-locomotive-heritage-series