Earlier quoted context omitted.
I don't think this is quite right. Little Boy (Hiroshima) was test-fired at Trinity. Fat Man (Nagasaki) was the one that was dropped without ever being tested, but it was plutonium.
Both the Trinity test and Fat Man were implosion type weapons: http://en.wikipedia.org/wiki/Nuclear_weapon_design#Implosion... I don't think Little Boy's design was tested prior to being dropped on Hiroshima.
Ah. My error, I thought Trinity was a uranium/Little Boy type.