> There were a few cases you can find on Usenet of people saying "open source code", but that's not the same thing; "open" there modifies "code", rather than modifying "source".
Ah, come on! You can't be serious.
"Source" in "Open Source" is short for "source code", and no other meaning of the word "source". The history page you link doesn't state it explicitly, but they do mention "source code" a few times, in addition to mentioning no other meaning of the word "source", so I think it's pretty reasonably to assume that these OSI people, like many programmers, when speaking about "source" were using it as a short for "source code".
Because really, a "source" (in the meaning of "origin") that is "open", what does that even mean? That things can flow from it? Sorry but you are also aware of the term "closed source" right? Except that, if nothing originates from it, it's no longer a source. Yet if you interpret it as "closed source code", it still makes sense.
I don't really see how your link to the opensource.org/history proves your point, either. In fact it strengthens the other point as well. Sure it shows they decided to name their new licensing scheme "Open Source" (where it seems to me, "Source", from the context to be short for "Source Code") -- even though people had (naturally) already been using the term "open" for source code that is publically available.
So you can make the point, that possibly, they were the first that shortened "open source code" to "open source" and using that as a brand, while at the same time hijacking the meaning to something much more strict (namely excluding of open non-commercial licenses).