I did that and then accidentally snagged a bit of membrane and it bled a little, so there's still veins apparently. Hopefully the little bit of bleeding won't hurt it.
If they seem to be developing faster than the others you might have hot spots. Are you using a still air or forced air incubator? Still airs are more likely to have hot spots but I've heard forced airs can sometimes have them too. Moving the eggs in different positions around the incubator so they're not always in the same spot will help. I wouldn't worry too much about them developing a little faster, just put them into lock down day 18 and they might hatch a little bit earlier than the others.