I don't usually get late term ultrasounds (my docs just don't do them, no judgement meant).. but my 2nd daughter was born at 37 wks 0 days and was 6lb 13 oz. Her weight helped her maintain her body temp. being nearly premature so that was great!
My 1st was born 41.5 weeks at 8lb 4 oz. I think I just make slightly bigger than avg babies... But that said - those sizes at those gestational periods are nothing crazy. I wouldn't worry. Plus, they SERIOUSLY are almost always a pound off it seems when they make those guesses.
This little one has been measuring on the big side the whole pregnancy. But I was told he was estimated to be 7lbs 8oz at 36wks.
I was also told they could be a pound off either way (high or low).