Late term ultrasounds are super unnecessary. I had one on Monday and she's so big you could hardly see her, the measurements aren't very precise [notoriously a 2 pound buffer on size estimates] and they can tell based of fundal height if there's any need to check via ultrasound on amniotic fluid.
Doctors can tell based of feeling your abdomen if baby is head up or down because they do it all the time but again if there is any cause for concern they will do an ultrasound.
I guess it was nice seeing her but there was no medical need to do an ultrasound. Even I could tell she was head down, spine along my left side & feet kicking my right side just by the way she moves - didn't need an ultrasound to know that & since my fundal height has been great we knew I wasn't having a problem with my fluids.