lack of 3.3 on a 4670?

Hello.

According to various sources online, this Radeon HD 4670 is capable of
OpenGL 3.3, but even with the recent 10.0 release, I only get a 3.1
core context:

$ glxinfo | grep OpenGL
OpenGL vendor string: X.Org
OpenGL renderer string: Gallium 0.4 on AMD RV730
OpenGL core profile version string: 3.1 (Core Profile) Mesa 10.0.2
OpenGL core profile shading language version string: 1.40
OpenGL core profile context flags: (none)
OpenGL core profile extensions:
OpenGL version string: 3.0 Mesa 10.0.2
OpenGL shading language version string: 1.30
OpenGL context flags: (none)
OpenGL extensions:

$ uname -a
Linux viper 3.12.7-1-ARCH #1 SMP PREEMPT Fri Jan 10 08:50:35 CET 2014
x86_64 GNU/Linux

Is this simply due to not-yet-implemented features on this hardware?

M