Prove to my insurance that my car has ABS?

I have a 2001 Saturn SL1. It has ABS. I know because the dashboard
light says so, and it has saved me from skidding numerous times.
My insurance company is not convinced. Their underwriter says that
ABS was not standard on my car. That may be the case, but my car
_HAS_ ABS. I'm not the original owner, so I don't have the original
sticker. Is there any proof I can offer them so I can get the ABS
discount on my insurance? Does the VIN have a code that identifies
this option was implemented?? Is there some other sticker somewhere
that would indicate?
Thanks
Theodore