Curiosity on LEGO Digital Designer

As I have used the designer to do a couple key MOCs lately, I did notice something interesting.

When you make instructions for your model, the applet in HTML will graciously provide you a full inventory of what's in your build, like a conventional LEGO Set. I have noticed that for every part in conventional LDD, the 6 or 7 digit part ID in LEGO's book is provided. For every part you chip in from "LDD Extended" there is no number, however. Also, parts that LDD 4.2 predated, namely parts in Olive Green don't show in LDD. IE: when I did my Tri-Rails, the Medium Azure pieces from the 41015 Dolphin Cruiser were not ID'd.

The idea this suggests is that beyond the wealth of parts that are already immediately available, there are more that have an ID with LEGO.

Here's a visual of what I'm talking about:

And as such, I'm wondering if one can order parts like these direct or say, through LUGBULK. Frankly, if so it would be GREAT... I could definitely use a broader variety of pieces for my Tri-Rail rotems, for example These are parts that could have been produced in order to make company models, ie. Miniland.

Most obviously parts that are no longer in production will not be available. But we're talking future parts here, so this is something to think of and perhaps to research for the coming year.