Effective Aug. 09, 2017, Colorado repealed the ban on switchblade and gravity knives, but...(there is always a "but")
Kniferights.org added the following:

WARNING: Automatic (switchblade) and gravity knives are still subject to Colorado’s concealed carry blade length limitation of 3.5 inches or less.

WARNING: Unfortunately, while the state law has changed in Colorado, without state knife law preemption a significant number of municipalities in Colorado currently still ban switchblades mirroring the old state law. Among them is the state’s largest city, Denver, as well as Aurora, Boulder, Colorado Springs and Lakewood. No doubt others do as well and this patchwork of local bans is potentially waiting to trap unwary knife carriers.

No legal test yet.