This isn't really my area, so I'm probably wrong... I'd always assumed that RAW files were, well, raw data straight off the sensor (or as close as possible)? In which case, you could standardize the container format, but I wouldn't think it was possible to have a standard format for the actual image data. Would appreciate if anyone could correct me (a quick skim of wikipedia didn't clear it up)
Typically they are not to my knowledge! Though I am also not an expert. Most camera makers apply a fixed sensor profile, and possibly a dark frame to remove noise before writing out the values to whatever file. Some of them may apply lens optimizations to correct distortion or vignetting as well.
On top of that, I hear the RAW format on some smartphones is saved after the phone does its fake-HDR and computational photography bullshit, so it's even further from "raw" with those cameras.