It may depend on the nature of the camera's high ISO noise reduction. I'm pretty sure on my Nikon (D300) that high-ISO noise reduction affects both raw and jpeg, i.e. the raw file DOES contain the resulting noise reduction. I guess it's possible that on some cameras the noise reduction might be applied only on the image data that is then converted to jpeg, and any raw file is unaffected. Check the camera manual.
Correction, I was wrong!
I've just tried a few shots at max ISO with "High ISO NR" set to off, normal and high. It affects jpegs (including the preview stored in the raw file), but apparently not the raw files themselves. This is odd: neither the NIkon manual nor the Thom Hogan manual mention any difference in high ISO noise reduction between raw and jpeg.
So I think what you read was right for my NIkon: high ISO in-camera noise reduction is not applied to raw files. And my camera manual didn't mention this, so I suggest trying it as I did and see what happens.
Sorry for getting it wrong first time. You learn something new every day...