Yes, and widely.
The first Ruger MIM was the M77 extractor about 14 years ago.
Since then it's spread and it'll continue to spread.
Their MIMs are outsourced, so far.
Ruger's found that CNC machining is more efficient than casting in some larger areas, and that MIM parts work just as well as cast in other smaller areas at lesser cost. MIMs generally don't require the same level of final-finishing as cast parts do.