That's a silly question.
http://www.alexa.com/siteinfo/nuklearpower.com#
The answer is actually no, according to these stats 8bt didn't have a huge impact on the site overall, seems the ween towards the other comics was quite successful.
You can see pretty clearly that in 2008 it was quite busy, but it hit a rapid decline that settled down around the beginning of 2009.
Suddenly, mid 2009 caused a giant spike and the site got a 50% traffic increase which settled down only after about 2 months after the comic was "finished" aka put on indefinite cliffhanger, no traffic change was caused by the epilogue.
The odd thing is that more people than ever have got to NP.com through search engines recently, though that just might be due to googles ever expanding waistline... I know I use my google bar at least 10 times more than my actual address bar.