GIMP :: Color Matching A Dirt Texture

I've been trying to work on my color matching skills (which are poor). The long term goal is to be able to match a sample texture's color with other texture samples that have been de-saturated then re-colored to match the original so that they can blend in and out of each other easily.

I'm using the attached image as a sample, then de-saturating it and trying to get the same color in the de-saturated image. I've tried using different mix modes, different base colors, playing with levels, colorize, and other plug ins - but I can never get quite the same color across the image. Its either too brown, too red, too yellow, etc. I was wondering what methods would be used to get a close to exact result - and for that matter, if it is even possible to color match only using 1 base color as a overlay (or other mix type)?