Just a guess as Cobra 427's aren't my thing but I'd say in terms of originality, the carpet would be wool. Karvel is a modern carpet weaved to look like Wilton wool but it's a modern
synthetic. Probably a lot cheaper than wool though, so if cost is an issue, it may be an alternative.
The rear bulkhead covering sounds correct but it may have been real leather. I'm not sure but street cars got more attention to their interiors than did comp or S/C versions.
Larry