The Denver police officer i talked to, said yes they are illegal. Spyderco factory outlet in Golden, said it depends on interpetation and would say yes illegal to carry.
I called criminal laywers and they never had a case with a spring assisted knife.

The "End All" call, which i just made but got hung up on would be a call to your local police dept and talk to the Watch Commander in charge. I was just about to talk to him when he put me on hold. Sounded like he was in the bathroom peeing and the phone disconnected. I will call again later.