Magic instead of Atoll
A very interesting question, actually (thinking about it brought me to idea for another future article).
Iraqis say they were happy about the R-60MK (AA-8 Aphid), and it seems this was the case. They not only scored a few kills with that weapon during the war with Iran (I intend to tell one of stories in question, sometimes in the future), but kept it in service right until the (second) end of their air force, in 2003.
The same sources say they were very pleased with the R-13M too.
So, why were Magics added to few of IrAF’s MiG-21bis?
I don’t have a definite answer, but it seems that they did so because the weapon was available and — knowing they’re going to war with Iran — Iraqis decided to put it to test.