How old are the MNCR and MNCX reporting marks?

Hey!

I'm a bit confused about how long the MTA have been using the MNCR and MNCX reporting marks on their equipment. Do they actually pre-date Metro-North (1983)? If not, then what reporting marks did the "M-Central" equipment bear during Conrail's operation of the Metropolitan Region? Simply the old MTA "M" with CR marks?

Thanks!

only MN reporting mark is MNCW, there are no others.
Passenger equipment normally does not need reporting marks as name of owner is clearly spelled out on all Passenger equipment.
The initials MNCR are just that initials, not reporting marks, the MNCX applied to some early MofW equipment was done in error.

Passenger equipment send by manufacturers or rebuilders and insured by that contractor, usually carry a sticker at or near car/locomotive number like BBRX or MPEX etc.