OMI's brass N&W Jordan Spreader #514727

[NW Modeling List]

Hello, I'm new to this modeling list and will ask several questions over time. Here's one, I have an Overland Models brass N scale jordan spreader in yellow paint with black lettering and the road number #514727. Am curious, when was this scheme used on Jordan Spreaders and the history of this particular prototype? It seems that I've seen pics of N&W spreaders in MOW green & white, black and white in the steam era and also one spreader in the 1970's black and white type scheme in Jim Nichol's color guide book. Many thanks for all your help!
Dave Grigsby