Just checked and mine is part of it as well, not that it matters much in my case since my cats are gone and ECU is tuned.
Text from the site:
General Motors has decided to conduct a voluntary emission recall involving certain 2011-2012 Chevrolet Colorado and GMC Canyon vehicles equipped with a 5.3L engine. The design of the fuel control system did not adequately control carbon monoxide emissions from the tailpipe under certain operating conditions.
Dealers are to reprogram the engine control module with a modified fuel control calibration.
2011, 5.3. Received an emission recall notice last April. GM is offering to reprogram the ECM for me at no charge. I don't think so. No inspections in this state. Filed notice in folder with other "Colorado" related documents.