That is the Phalanx Block 1B.
From that 2006 post:
Here’s a nifty diagram of the Phalanx family evolution from Block 0 up to the Block 1B (and actually beyond Block 1B and into the SEA RAM program which replaces the 20mm gun with a Sea Sparrow/Sidewinder mongrel missile for greater range…but that’s another post). Click for a better look:
I know that there is a SeaRAM (which replaces the 20mm gun with a Rolling Airframe Missile launcher) on the USS Independence (LCS 2) but I don’t know if any other ships have it yet.