I think Galen and Bill are right, in that people did not refer to aventurine, regardless of it's color, as lutz on machine made marbles until after they started adding it to some of the JABO private runs.
However, it is notable that people still refer to "blue aventurine" or "green aventurine" even on the new JABOs, and that the "lutz" term is used to refer only to the thicker golder aventurine that is displayed on those marbles, likely since it is reminiscent of the gold "lutz" on some hand made marbles.
Since I'm not that much of a purist when it comes to terminology, it doesn't really bother me - I know what people are talking about. And honestly, have you ever seen the amount or type of gold "lutz" that appears on some of the new JABOs on any vintage machine made marble? If so, I sure would like to see some pictures, because those would certainly be some sweet mibs!
All IMHO and FWIW.