Yeah they are pretty legendary. Frankly, I think it is pretty unlikely that they would have selected CDO components but it is certainly firmly in the realm of possibility.
Separately, I just checked their careers page and no software engineering positions. Seems like there would be a lot of automation and systems work to do there, but I guess it is possible that they just aren't hiring for those roles right now.
It was famously suggested that they caused the 2008 market crash: https://www.propublica.org/article/all-the-magnetar-trade-ho...
https://en.wikipedia.org/wiki/Magnetar_Capital