The frame was made by Giant in Taiwan, April 1984 (G0484 on right dropout). It does appear to be a "World", but the '84 catalog shows the World as being available only in Red or Warm Silver:
1984 World catalog page
The 1984 World Sport, on the other hand, was available in Black or Sky Blue:
1984 World Sport catalog page
The World Sport frame had 4130 Chro Moly main tubes, while the World frame had Hi-Ten carbon steel for all the tubes. Also, the World was a ten speed (five cogs) and the World Sport was twelve speed (six cogs). It's hard to tell from your photos, but it looks like yours only has five cogs, which would make it a World in spite of the blue paint.
Your bike sure looks like a World, but the Sky Blue paint really throws me.