Our son was born at 41 weeks by section as he was too big to descend, but this was only found out after 12hrs of unsuccessful labour. He weighed 10lb 7oz & I'm 5' 8" so he was by no means huge for someone of my stature. The actual section took less than an hour once the theatre was ready, but this was an emergency, so would guess under "normal" circumstances & depending on how busy they are, the checks they do etc you should probably hear something by lunchtime.
I would suggest buying 1 outfit up to the 12lb range & then a range of bigger ones, say 3-6 & 6-12 as I found that the newborn size lasted about 3 weeks & we were inundated with that size. Mum to be is probably organised with baby grows etc, but get a bigger size of these in case the newborn ones she has got don't fit. My son lived in babygrows for the 1st month anyway & outfits were a waste of time as he was always being sick on them!
Best of luck to all! Oh & remember to ask for gift receipts in case things need to be changed!