From what my research shows, there seems to right or wrong especially if the ship you are doing is generic of no specific general freighter style with no cranes which is my situation.

Mornin' Ron, A 'Tall order'!
As far as I know there ain't no such animal!
How could there be? Each shipping company has there own ideas and 'House' colours. Colours may also change during the ships working life, e.g. if it is sold on to another shipping line.
Best you can do is Wiki the ship you are modelling.
If it is still in service you should find it on the various Maritime Tracking sites (try www.marinetraffic.com and search the ship's name) or relevant Shipping Company site. if you know the company name Google that. Good luck, cheers, Doug 😎