No on the Steam activation. I wouldn't worry too much though. The regular version was half off a while back, so seeing this for $20 in the next big sale is not unreasonable.
I'm not 100% sure but I think they rolled back the drm a bit so changing video cards doesn't necessitate a reactivation.
Also I believe ubisoft eventually removes the 3-activation limit on their games after they are out a couple years but not sure if that was an isolated case or general policy. I believe they did this to Anno 1404.