New Colorado license plate with 2004 expiration, and 2004 tab for Colorado counties that fall under the emission law.

UPDATE: (April 12, 2003) I can now verify that there will be just one color of tab for 2004, black on green, for the entire state. This comes directly after the state has done away with emission stickers in car windows, effectively making the emissions program impossible to enforce, making me question its necessity.