Is a JPEG at 0% compression a RAW image?
It would be close but not exact. The way you would get close is to set the 8x8 quantization matrix to all 1's. In JPEG compression, the image is divided into 8x8 blocks, discrete cosine transformed, elementwise divided by an 8x8 quantization matrix, rounded to the nearest integer, and then (usually) Huffman encoded. The primary problem with being perfectly lossless is that the DCT produces a fractional result. So even if you set the quantization matrix to all 1's, the rounding step would lose information.
Care to enlighten me as to how one sets jpeg compression to 0%?
Also, no, RAW formats are not simply uncompressed, but largely unprocessed data as well (certainly less processed than what you get from an out of camera tif or jpf.)
Raw formats are indeed compressed; they're just losslessly compressed.
Finally, there is a true lossless JPEG format, though it is distinct from the usual JPEGs.