Not a dealbreaker, but I sure hope they are. I do remember there were a few shareware demos included. Can anyone remember what they were?

Nah, the original CD shareware games (Duke 1 & 2, Raptor, Cosmo, etc.) aren't included here.
BUT you can easily find the shareware all over the tubes.

I think you're talking about the original CD release of Duke Nukem 3D v1.3d - NOT the Atomic Edition (1.5), which added the fourth episode - which indeed came with Duke 1 + 2 (registered) as a bonus feature.
They are unfortunately not included here. I think 3D Realms is still selling them for 6 bucks apiece through their webstore.

Yep, 3DRealms has them in their store.
http://www.buy3drealms.com/
$5.99 each.

If you are just wanting the shareware demos--not the full versions--you can find them on any of various sites including 3D Realms' own site (Duke 1, Duke 2). You will need to set them up in DOSBox yourself but they don't need any special configuration so this isn't too much of a hurdle.

Duke Nukum (yes that is the first games title) may not even need dosbox on 32 bit windows NT due to the fact it only had PC Speaker sound. Duke Nukem II has ADlib sound and needs dosbox. Also Duke Nukum was episodic so you get 3 exe files to play the game.
Duke Nukum
Duke Nukem II

it would be really nice if GOG could include the original games with Duke 3D with extra goodies

now that would be value

I too would love this, o lord of necromancy.

*bows, prays*

It'll probably never happen, for the same reason they weren't included with Duke Atomic: the people who contributed to them in some ways wanted royalties for every copy of Duke 3D sold, even though they were included as free bonuses.

the same programmers who did the first two worked on DN3D so apogee was already paying them 3DR just decided not to include bonus registered games in Atomic since they already included a 4th episode.