new spokes needed? XTR - Pro II

It totally depends on two things -

#1 is the hub measurements of the two hubs. They have to be exact or very close to it. It's highly doubtful. The Wheelpro Spoke Calculator will tell you everything you need to know.
#2 is the age and condition of the spokes. Almost zero wheelbuilders will re-use old spokes or rims. They have a reputation to uphold. You may reuse the spokes if none are damaged and they are of a reasonable age.

Bottom line - new spokes for you.

nothing wrong with reusing spokes if they are in good condition and the numbers work out, but it's ultimately up to the wheelbuilder and what he/she is comfortable with. i'm about to reuse wheelsmith db spokes to rebuild a king iso wheelset onto hope pro II (SS). no qualms whatsoever, but i'm the wheelbuilder (both cases), it's a personal wheelset, and i'm ultimately responsible for the results.