No you didn't.
Normally archive and install is the default. However, with Snow Leopard, the default was "upgrade". That means it's the same System folder with many, many, many files and folders replaced. An archive and install will make an archive of your old system folder and add an entirely new system folder, hence "archive and install". There's no archive with an upgrade.
But you are wrong. The default "upgrade" is an improved "archive and install". Improved in the sense that you don't have to clean up the old install after it is done.
So the installer installs the OS in a new System Folder and deletes the old one when done.
S-