Top 5 in Gunmaster and no unlock?

I am awful at Gunmaster, truly dire. So when I thought I hit top 5 and got no unlock I was gutted. Figured I was wrong but browsing games I spotted I hit top 5 or am I missing something?

http://battlelog.battlefield.com/bf3/battlereport/show/65260712/4/182421889/ [battlelog.battlefield.com]