8.5 pound baby?

Autumn • Wife, and momma to an almost 2 year old 💙
At 36 weeks I had a ultrasound to see how baby is measuring, and he is already 7 pounds! I know they can be off but it would make sense because his dad is a pretty big man! But my question is if I make it to full term baby would be 8.5 give or take so would he still fit newborn for a week or two or should I try to exchange all the newborn stuff we received and bought?