not entirely true. The guy heading the project at gearbox was a member of 3d realms and helped create duke nukem 3d.
During the live show he also talked about the fact that instead of just picking up the game, he picked up several 3d realms developers that were the original hands at creating duke in the first place and put them on the team with gear box to get this thing rolling. Not sure exactly what they did on the project besides giving direction, but 3d realms had a hand in it as well.
The guy said he did all this as a way of giving something back to the game and people that got him started.
But of course the fact that its coming out and as soon as next year, is all gearbox haha.