Yeah at 5 weeks you'll have a good idea for sure. If the others are isa browns than you'll have to wait until they are 5-7 weeks to be relatively certain.
These are golden comets? If so, which they look like, my guess is that they would be roosters if they all look like this. If I'm not mistaken the hens are tan and red ish where the boys are white and tan. But then again, I am still new to this too... search for a thread on sex linked Golden Comets.