Yes they are removable....AND you can now buy stainless steel replacement knobs for them!!
But i have 2 from the 70's and 80's and the6y go into an oven as long as it's not hotter than 375....have done it many many times!
Linda C

Here is a link that might be useful: knobs

Linda:

You are a goddess! Thanks for the helpful link and good answer.

Denise

I have a couple of those old Le Creuset ovens (from the early to mid '70s) - yes, the plastic covers did slide off the metal knobs underneath. And yes, in my careless youth I did melt one of the covers onto the underlying knob.

As you now know, the good news is that you can get replacement knobs. Actually, long before those nifty stainless knobs were available, Le Creuset sent me a black replacement knob for my melted one.

The bad news is, I can't get the screw out to unscrew the damaged knob. It's rusted in place. Or something.

However, since these particular Le Creusets have ridged bottoms (on the outside, not the inside) I can't use them on my current glasstop stove anyway, so in storage they sit - with their replacement knobs tucked safely inside them.

Oh well.