In «Mobile 3D Graphics with OpenGL ES and M3G»(2007) book there is a mention of Nokia N93[0] as the first one with OpenGL ES "in hardware":
> From the left: Mobira Talkman, Nokia R72, Mobira Cityman, Nokia 3410 (the first GSM phone with a 3D graphics engine), Nokia 6630 (the first phone to support both OpenGL ES and M3G), and Nokia N93 (the first phone with hardware acceleration for both APIs)[1,2]
N.B. Nokia N95 (March 2007) is a successor of Nokia N93 (April 2006).
Many of those models used software rendering implementation.