We shouldn't and we won't because there's no real distinction between the two.
As Wil pointed out, your proposal only muddies the situation instead of clarifying it.
As Fly points out, using
LBB1-3 alone still results in something
3I-ish.
The idea that
Traveller originally was some sort of do-it-yourself generic sci-fi RPG setting kit is as old as the game. It's also fundamentally incorrect or, putting it more politely, greatly optimistic. From the first and thanks to it's technological and sociological choices,
Traveller constrained the range of settings which could be constructed from it's rules.
This
article discusses that constrained range of settings as part of it's examination of
Traveller's source texts. The article contains a chart listing 14 of those sources and the ease at which
Traveller could be used to create each source's setting. The results are eye opening. On a scale of one to five, only 3 of the sources rate 4 or better.
You can, for example, use
Traveller to create a
Star Wars setting
IF you make your own rules for FTL comms, give fighters weapons that can damage ships, change jump drive's range and size requirements, and dozens of other things.
Putting it another way,
Traveller isn't a pile of lumber waiting to be shaped into a house, boat, dinner table, or whatnot. Instead,
Traveller is a preexisting object which with varying levels of effort and success can be reshaped into a house, boat, dinner table, or whatnot.