SRAM replacement dub crankset, is this pre-greased? I'm replacing the NX cranks on my bike with X01 cranks, all of the install videos I've seen show people greasing the cranks but these look like they're pre-greased. There's blue/green stuff on the spindle and brown inside the socket on the crank as per the pictures.
Is this grease and is this sufficient? Should remove it and replace it with this grease I have?
My old spindle didn't seem to have very much grease at all and it was black so difficult to compare.
Yes that is grease, in my opinion that is about the bear minimum amount intended to help prevent seizing between the two interfaces. I usually leave it if it is my own bike and just add a bit more additional grease, as most cycling greases will not have any interaction with each other. In a professional setting or working on someone else's bike I would remove it and use all one type.
If you watch Sram's installation videos they are definitely a bit more liberal with the application spreading it both on the exterior of the spindle, and in the grooves that interface with the crankset.