It all depends on what you're used too. If you normally go to bed at a half decent time and suddenly you're going to bed at 6am then nothing positive will come out of it. You want to maintain a regular sleep schedule when attempting to lucid dream so you can learn your sleep cycle patterns. Many people will tell you that you need to sleep for a bit before you dream. If you start messing with your sleep schedule it will be incredibly difficult to figure this out.

Of course some people find going to bed later positively affects their attempts and everyone's different. So although I wouldn't recommend staying up that late for obvious health reasons as long as you can maintain a persistent sleep schedule it won't hinder your efforts too much.