As many of you may have heard, Gearbox has not only picked up the slack to finish DNF, but they've bought the Duke Nukem IP from 3D Realms in its entirety.
http://pax.gamespot.com/story/6275307/gearbox-acquires-duke-nukem-ip/?tag=latestheadlines%3Btitle%3B1
Now I know I'll always be able to download Manhattan Project since I already own it, but what happens to the game on GoG as a sellable product now? Has 3DR made arrangements to sell its legacy catalog like Interplay with Fallout and Redneck Rampage? If not, will GoG talk to Gearbox about keeping the Duke on their service? Or is this the end of the road for buying Duke here? Just curious, and thanks for your time everyone.

I was wondering the same thing.
Both games are still listed on their pages as being published by Apogee. But whether or not that means Apogee retain the right to sell those games, or whether it means events simply haven't caught up with GOG yet, I don't know. It would be interesting to find out though.

The new apogee sells the games through GOG.com for the old apogee. so the game will still be sold here as long as Apogee LCC gets to keep the rights to duke.