fan shroud fitment is the same from at least 05-14, even though there was some design changes 500/700 w etc, fitment is identical the only difference would be if is was a 28 vs 34 inch but i have only seen the 28 inch on the silverado'sI wouldn't conclude that, necessarily. A 2-row radiator is always going to be significantly thicker than the single row OEM design. The only way I can think of that you wouldn't need to trim the fan shroud is if yours came with a thicker core radiator than most from the factory (an SSV/PPV thing, maybe?), or if your fan shroud doesn't have the lip on the top or bottom - either because it's an aftermarket design or perhaps because someone else already trimmed it for a thicker radiator.
this includes the hummers and avalanche also, the shroud I am currently using came off a hummer