Contact GM customer service and they should get you to the right place. They used to do this as I know many people in the cosworth vega owners association would get them for their cars.
You may have better luck contacting the NCRS
I don't know what that means but you can call their gift shop. If they don't have it, they will guide you. Their website has their number and email addresses.
Thanks! Your answer is awaiting moderation.