I've seen some older kilts fade in very interesting ways, so the color change here does not surprise me. (The last kilt OC Richard gave a picture of is a perfect example). However, from the photographs posted, your Cameron kilt appears to be made from a smooth worsted cloth, not the regimental cloth, which is a worsted/saxony blend and has a rather more "fuzzy" appearance. Plus, as you said, the pleating is not the same as the Cameron Highlanders. The other thing I noted is that there is no MoD label in the kilt -- which could simply mean that the lining was replaced at one time and whomever did it did not bother to replace the label. But it also could mean that this is not a military kilt at all, but rather a civilian kilt, or perhaps one made for a pipe band.

In any case, it is obviously an older kilt, and I personally think the unusual fading of the tartan is quite attractive.