The original installation media for Mac OS X Snow Leopard was a 10.6 DVD. The DVD was only updated once to version 10.6.3. In order to provide more frequent updates to users, Apple is now slipstreaming the latest version of Lion directly into the download. Upon fresh installation, no updating is necessary!
If you purchased Lion from the App Store prior to October 12, 2011, you have either 10.7.0 or 10.7.1. To re-download and update your App to 10.7.2, follow this simple procedure.
1. Delete your existing copy of Install Mac OS X Lion.app from Applications folder.
2. Hold down the alt/option key on your keyboard, and click the App Store icon.
3. With alt/option key held, click on Purchased
4. With alt/option key held, click on OS X Lion
5. With alt/option key held, click on Install
The Installed button should change to Install, allowing you to re-download Lion. When the download finishes, the app will automatically open. The updated 10.7.2 Install Mac OS X Lion App can be found in the Applications folder.