If the police were to judge by license plate alone and had a passing knowledge of Colorado plates, I might get by. When Colorado first began issuing its current series, it continued issuance of truck plates for pickups (with a vertical TRK code) as previously. Then partway through the series, they stopped issuing these plates and only issued standard passenger vehicle plates. There is no obvious reason for a different plate for pickups, since nowhere in Colorado that I'm aware of is there any prohibition on trucks on any public road. My registration says "light truck", and there is no "commercial vehicle" category in the state. So, my truck has the same kind of plate as any passenger vehicle.
Somewhat ironically, since light trucks pay a higher license fee, there is a special category for pickup truck owners that only use their vehicles for commuting or recreational use: recreational truck, and the plate has a vertical "RTK" code. Those owners pay only the equivalent passenger vehicle fee. That seems kind of analogous to the option in New York to register a pickup as a passenger vehicle if nothing will be carried in it. But, I'd probably be more likely to be stopped in New York because of unfamiliarity with the meaning of the plate. I don't use this option because I do carry cargo occasionally, such as building materials, and could be stopped with a RTK plate. I also wonder how the tool box I usually have on the truck, even when hauling my recreational trailer, would be viewed.