The coloration looks more uniform than the Westinghouse micarta I've seen, so it could be just a modern piece of micarta dyed that color. Not sure there's a way to prove whether it's Westinghouse at all definitively.
What knife is it? That's a better place to start. If it's a production knife, they're definitely not going out and trying to buy vintage micarta off of ebay for it. If it's a custom, it's more possible.