Beautiful specimen you have there. I believe some letters have been wiped out in the top line and that the inscription is actually "Industria Argentina". Despite what one might think, it's probably not a recasing, and I have seen other Omegas with a similar case. It refers to a very particular period and set of politics during the Peron period. Here is a bit of info I managed to dig up:
INDUSTRIA ARGENTINA
In the era of president Juan Perón 1946-1955 and 1973-1974, Argentina was governed with what was called Peronism or Justicialismo. That ment that Perón with his govermant took control all foreign trade and import. Perón’s idea was that Argentina ought to be fully self sustained in all areas in trade as well as society.
In practise, this ment that all industrial manufacturing and artisanal production was ordered to be made in Argentina, not imported from abroad, unless absolutely neccessary. This happened in most of manufacturing, but not with watch movements. For watches Argentina didn’t have suitable expertise so it was allowed to import watches from Swizerland and other countries. But Argentina had very strong national jewelry and goldsmithing trade, so only watch movements were allowed, all watch cases had to be made in Argentina. Many watch manufacturers therefore abided and had their watch cases made in Argentina. For example Omega, Girard Perregaux and Jaeger LeCoultre had their own manufacturing in Argentina. These watch cases were usually stamped Industria Argentina. It is generally acknowledged, that watch case manufacturing quality in Argentina was equivalent to Swiss production.
Most likely your watch case was made by Omega in Argentina and stamped with Industria Argentina stamp, while the movement was made in swizerland.