Ramzi / skull / nub theorys???? :)

Hiiii .. Here's 2 scan pics .. One done at 6 weeks + one at 12+5 :)
Can anyone tell what I'm having?? + how accurat is ramzi/skull/nub tests?
Both were done abdominally no transvaginal .. I heard somewhere that ramzi has to be switched when the scan is abdominal?
Please give me some guesses :) I'm 16 weeks now .. Another 4 to wait until 20 wk scan + Im so impatient :( lol
Thanks ladies :) xx

6 WEEK:
http://i1247.photobucket.com/albums/...s/a714ebdb.jpg

12+5 WEEK:
http://i1247.photobucket.com/albums/...s/41b33b4e.jpg

Boy