This is my early model Expanse CE1000 lower that I bought in early 2016, the roll marks, laser etched LE serial number, Colt Defense and QR code at the right side of the Colt Defense marking are the same as current LE6920 series carbines.
My other 6920 upper is on the Expanse lower half.
The right side of my Expanse lower (and also Expanse upper shown), I had changed the hammer with a standard Colt semi auto and H (heavy) marked buffer.
To answer your question I would think it would be almost impossible in getting some Expanse parts on the production LE6920 because there are no Expanse parts in their CT factory, and the workers union won't allow it.
The stripped lower receiver are the same with the Expanse and current LE6920, except some parts of the Expanse lower are different.
The hammer on the Expanse are the Colt match low-mass nickle finished 6 lb. pull which are mostly used on Colt Accurized Rifles and Competition rifles, they have a lighter pull weight and smoother than regular Colt semi auto triggers.
Magazine catch varies some have a one piece catch and some with the standard two piece catch.
Selectors on the Expanse are the old type with smaller size lever, not reversible and they have an indicator line on the right side.
Buffers on the Expanse are not marked standard carbine buffers, not the usual H marked heavy buffers on the other Colt carbines.
The castle nut staking on the Expanse are round shape, other Colt carbines have a square shape stakes.
I bought my Expanse mainly to have another extra lower half, I did replaced the hammer from my other 6721 AR-15A3 Tactical Carbine, replaced the mag catch with a standard Colt two piece type, and the buffer with a Colt H heavy buffer.
The selector is fine for now but I will replace it later on with an ambidextrous type either Colt, KAC or LMT.
For reference here's another parts comparison older thread early this year (link below).
https://www.ar15.com/forums/t_3_12/708380_Colt-Expanse-Parts---What-you-should-know.html&page=1