[Taniwha]

essentially yes - the video channels and the docsis channels are distinct - and your street or close neighborhood may share the same docsis (and on-demand TV) while you city might share the same broadcast channels.

The document refers to "qam-lock" IMHO wrongly (I was a cable protocol/encryption wrangler in a previous life) - "qam-lock" is more a matter of tuning to a channel, sampling it to extract the signal (this means extracting a clock from it) then running the signal through enough of the error correction and framing logic so that you can extract the transport stream packets

That's "qam-lock" - at this point you still don't know what's in the stream - you could just look for 0x1ffe PIDs and decide you have DOCSIS - video qams will carry PAT tables in PID 0 which will point to PMTs (which can be in pid 0x1ffe) which in turn point to qams and PIDs containing video/audio/CA/etc (details vary greatly between implementations). Which is a long way of saying "just looking for PID 0x1ffe may not be enough"