Is there something with that color that is removable? Maybe a fuel door or anything else that you can remove. Take it to the body shop supply house. They will scan it and make you an exact copy. Some body shops can scan the color on the motorhome and do the same.
Being a Newmar the master paint codes will be inside a cabinet door somewhere. Take the code to your local NAPA and they should be able to hook you up.
Or to a Sherman Williams AUTOMOTIVe store. that's where I usually go since that's what mine was painted with.
Now.. If you know the color names. and the "Scratch" is a small one you ***MIGHT*** (I'd give the odds in the single digit range) get lucky at Dupli-Color display at auto parts are us (Fictional but generic name).
I dang near fainted when I found one of mine there .