NYC Heavyweight RPO & Coach Road Numbers

[BRVRR]

I have been working on a heavyweight passenger consist for my NYC Hudson. I picked up 4-cars at a train show several months ago. A diner, observation car, coach and RPO, all in dark green, Pullman Green, with gold lettering. The dining and observation cars marked New York Central Lines have road numbers, but the coach and RPO, marked New York Central are numberless. I have been unable to find a source for proper numbers.[banghead]
Does anyone out there know what numbers would be appropriate for these two cars? Or, failing that, know of a website that I can search for proper road numbers?[:I]
Any help would be greatly appreciated.[:D]
Thanks in advance guys. [:D][:D]