The Walker and Lincoln lines are now known as Hein-Warner and are usually made in blue-and-gold (not sure if yours was).
There are a few outfits that offer rebuilt/reconditioned jacks; here is one shop that has photos of their old jacks. It looks like the Walkers they sell are usually repainted in a blue-gold scheme, but they have one in gray too.
The original color for vintage Walker Jacks was a dark blue. None of the old catalogs were printed with color photos but printed instead with colored images which were always the dark blue.
Here is a post I did a couple months ago. It does show a little color if that helps. I've put it away for the winter, I don't feel like it is a high priority for me, and living in Wisconsin, kind of limits my working on something like this for a while. I still need to find a wheel also. Please post a picture of your jack also.