Dynometer car lettering

[nw-modeling-list at nwhs.org]

I have two of the Northwest Short Line N & W dynometer cars.  One I have 
had for a number of years that I painted with a black roof, only to find 
out later they were brown.  I  have recently finished the (re) painting 
of both and I want to be sure I use the correct lettering.  I have 
 photos of  the prototype, some I took myself, but I am unsure which 
lettering to use. My original paint job was completed with Champ decals 
and applied one letter at a time. Since there was only one prototype, I 
 have a friend who wants the second piece when completed.
Can anyone offer any info?
Thanks
Dale Koglin