The FC-M952 (1999 to 2002) used either BB-M950 (made for XTR cranks from 1996 to 2002) or BB-M952 (1999 to 2002). Even though BB-M950 and BB-M952 were made in parallel for four years, they were both V1, it was just that the BB-M952 was a simpler (inferior) design. I personally haven't heard of any other splined XTR bb or crank.