The vehicle in question was in production by Chevrolet from 2004 - 2012. The SCTA rules allow you to run the engine that was available for that vehicle during those years. Example: 1968 4th Gen Chevrolet Impala. Built between 1965 - 1970. Some of the engines available were a 250 inline 6, 283, 350, 409, & a 427 V8. Any of these are legal in Production Category.
Call your Colorado a 2009 (1st year with an LS) and have fun. The SCTA doesn't look at Vin numbers....
You can also send your question to the Chair person for the SCTA Modified committee for a official answer.