The Wilson is a real puzzler. There are 2 basic types that seem very different, with lots of variance between them.
Even in the late 1970's Litho ink colors were mixed by hand. So a simple color difference is usually just a matter of who did the mixing that day.
Producing an exact copy fake would be nearly impossible. In theory It could be done, but the expense and technical skills required would be prohibitive.
I have some defenite ideas about some of the small differences, I'd been planning on posting about it anyway.
But in a different thread that doesn't involve reprints
Steve B