Ameraucana's can be tricky, but by 5 weeks, you should be able to tell for the most part.  Every now and then one fools you.  Post pictures and I'll have a look.
 
 
 
 
Okay guys, you are the experts and I'm excited to know if we can see pullet or cockerel at about 5 weeks old.  These are Amercaunas.
 
Chick#1 "Black Beak":  Coloring is Black and White...would this be splash or will he/she molt in as black?  Not that it matters, this is the calmest, sweetest chick I have ever seen.  Please oh please be a GIRL!
 
Chick#2 "Miss Lavender":  Coloring is Blue.  This chick is very friendly.  Even my 2 year old can hold him/her and he/she just is happy to sit on his hand.  I love the coloring of this chick.
 
Chick#3  "Daisy":  Coloring is White.  This is my daughter's favorite chick, but despite numerous attempts to tame him/her, he/she does not like to be picked up much, but will tolerate it.  He/She is happy to perch on an arm if he/she chooses to do so, but otherwise she prefers to roam with the blue chick.
 
Sorry for the delayed response.  I must be technology impaired or something because I cannot get my pictures to upload to this site, but I have posted them in the link below for viewing.  I've uploaded things to this site before, but it wouldn't work for me last night or today.  Wish I could post them on this site too, but it just gives error messages instead...
 
Here is the link to pictures of the chicks page:
 
 
http://www.benanne.com/Other/April-Easter-Chicks/29232323_8B2cDg#!i=2491407993&k=hrDs67z