i don't keep my insurance/registration in the glove box.
Can I carry concealed in my vehicle without a permit (even in Denver)? YES
See C.R.S. 18-12-204
(3) (a) A person who may lawfully possess a handgun may carry a handgun under the following circumstances without obtaining a permit and the handgun shall not be considered concealed:
(I) The handgun is in the possession of a person who is in a private automobile or in some other private means of conveyance and who carries the handgun for a legal use, including self-defense; or
(II) The handgun is in the possession of a person who is legally engaged in hunting activities within the state.
(b) The provisions of this subsection (3) shall not be construed to authorize the carrying of a handgun in violation of the provisions of section 18-12-105 or 18-12-105.5.