Yes, the software will install only the Gmail icon on your desktop. Here is a trick to have any link on your desktop. Just load the desired website, then click in the address bar with the website loaded and drag it on your desktop. It will automatically create a shortcut that will open the default browser to the address specified, in this case Gmail.
Secondly, browse Google and search for Gmail ICO. Save the file to your PC, right click the shortcut, go to Properties, change ICON and select the downloaded ICO file. It's way much safer this way instead of downloading program.s