Flatshading with glClampColorARB() (GL_ARB_color_buffer_float)

Is flatshading supposed to work when vertex color clamping has been deactivated with the following call?

glClampColorARB(GL_CLAMP_VERTEX_COLOR_ARB, GL_FALSE);

On nVIDIA cards (tested on Quadro FX 4400 & 4500) on Linux, flatshading seems to be deactivated when color clamping is deactivated. Is this the correct behavior? The specification doesn’t say anything about flatshading.

As far as i can tell it shouldn’t say aything about flatshading, so yes flatshading should still technically work.
It might be that the drivers are bugged, in witch case you could do flatshading yourself by setting the normals of the polygon to the same value.