Default list of Quicklook Plugins for a fresh LION install? What QL plugins "should be" in /System/Library/Quicklook/?
I have Mac OS X Lion 10.7.4, and that file is present. The file is copyrighted by Apple ("3.2, Copyright Apple Inc. 2007-2011").

Looking at the content of its info.plist file, I see that its purpose is generating a preview for files with a content type UTI equal to com.apple.iconset, which (as far as I remember) is the type of files containing a set of icons.

The computer I am using is a Mac Mini middle 2011. I don't actually remember if It came with Mac OS X 10.7 already installed, or it came with Mac OS X 10.6, and then I installed Mac OS X 10.7. I have also installed Xcode.
Probably that can explain why some computers don't have that plugin, and some computers have it. It could also be the difference is caused from installed software, or an update of the operating system.

I would not say the plugin should not be there. It is not a file created from malware, or viruses to cause any issue with your computer.