I found a guy that makes reproduction AC Cobra parts in the UK. I bought a set of dash knobs from him. I received them quickly and they look great. He also has foot box vent valves that are cheaper than some of the others that are selling them.

I bought them on ebay, but you can get hold of him on Facebook. Here...
https://www.facebook.com/Ashley-Hinton-245648178847505

I told him about this site, and I think he is looking into becoming a supporting vendor. I'm not sure if this is ok to post this or not, so moderators delete if it's not ok. I just want help others that may be looking for these parts.