No...for example 800x600, icons, etc will be giant. They are significantly smaller in 1600x1200, etc. For example, when you boot up in safe mode, and since there are no display drivers the default resolution is 800x600...only a few of my icons fit on the screen as they are greatly enlarged. This happens on both LCD's and CRT's.
Native resolution is something different, referring only to LCD's, as CRT's can physically change the resolution to match the input signal. Because LCD's can not do this, they rely on scaling, and if the input resolution is not proportional to the native resolution, distortion occurs. Read here for more info:
http://en.wikipedia.org/wiki/Native_resolution