Yes, girls will make a full range of noises lots very similar to the males... it's just that while males *might occasionally* let out a louder quack noise, only girls will let out a string of quacks... and usually they do it when they are upset, like not being able to see you, lol...
Until she...
If Lloyd all out does strings of quacks though, then Lloyd is a girl... they will make other sounds as well, it's just the girls that flat out quack like that, boys cannot...
At 8 weeks you should be able to tell gender by the voice... males have a quieter, raspy whaaap-whaaap-whaaap while females quack rather loudly...
This should help...
http://www.majesticwaterfowl.org/artquacks.htm
ETA: and you should come over to the house duck thread... lots of wonderful...