I don't think so. I think Adam -like me a while ago- just hadn't realised the exact relationship between objects and primitives and now discovered it on his own.
If we exclude the possibility that Adam and me are completely backwards and disinterested in the nature of ChucK or at least oblivious to the docs I'd say this means this subject needs more explicit clarification in the manual. We now know a lot more about objects, assignment and casting than we did -say- a year ago (at least as the relate to ChucK) but the manual lacks a comprehensive section on the matter.
Writing this would not be all that simple as a straightforward and brief explanation from a CS perspective wouldn't do because we have to assume readers of the manual might be encountering these terms for the first time.
Does anybody feel called to do a draft on the WiKi?