Yes, but only if the kernel knows how to switch back to textmode.
Knowing how to do that means knowing the state of the card and
how to set up the registers for textmode. That means you need
GGI to be able to see an oops while in graphics mode. (either
you stay in graphics mode or switch out, but you still need the
kernel support)
Sometimes people post "it crashes while running X" to linux-kernel.
It is difficult to debug these problems when there is no oops data.