Those 20 Mirage F1's, if bought by the Argentine Air Force will for the most part, be broken down for parts to keep the remainder flying. I'd be frankly surprised if buying these 20 Mirage's from Spain would result in a double digit rise in the number of operational aircraft available to the AAF.
And besides, even though these are the F1M's that were upgraded in 1998 for the Spanish Air Force that Argentina's supposedly buying, they're still hopelessly outdated when compared to the RAF's Typhoon's based at MPA, and possess nothing to counter the AIM-120C AMRAAM's and soon, MBDA Meteor BVR missiles fielded by the Typhoons.