I'm now wondering why you are weaning them so young? I didn't notice that bit with my first answer. We leave ours until 4 months, so 16 weeks, before separating them from their dams, and they are never fed creep feed. The ram shouldn't be eating any concentrates, especially in the summer, and yes, if the lambs are being fed creep feed then the balance of behaviour will be changed
So I suppose the answer to your question is, as always 'it depends'.