Woolen and Jean cloth color varied widely early in the war. As the Liberty Rifles research stated, there MAY have been some differences in fabric color coming out of England however, as stated, those nomenclatural distinctions may simply be different descriptions by different recording agents.
There is, however, a precedent for a variation of color with respect to kersey and kersey-like fabrics. North Carolina was (at least partially) responsible for supplying their own troops. In looking at correspondence from that time period, there seemed to be some concern over the varying shades of fabrics used in uniform construction. One indicated that the shade of gray used wasn't as important as bundling like shaded items together so that the various pieces could be issued at the company or regimental level to maintain a more uniform appearance. There is also an indication (with respect to NC at least) that while the vast majority of uniform fabrics were some variation of the wool-jean type, some locally produced kerseys were also used. It is also well documented that, with regard to NC head gear, colors were quite variable, with references to both blue and brown kersey being used as late as Winter of '61-'62.
I only bring up the North Carolina uniforms to point out that (especially early in the war) variability was the norm. Add to this, the south's reliance on natural dyes of questionable stability, few 'reasonable' colors can ever be ruled out. As far as EAC is concerned, recent scholarship points to a more dark-gray with a blueish tone as standard for the type. Dye lots and fabric types not withstanding, it seems reasonable to conclude that, at least late in the war, medium gray kersey would have been an anomaly, though possibly not, early in the war.
Just my thoughts, other's mileage may vary.