Mac – How to find out if an App in the Mac App Store is 64 bit

If you want an app-based app store alternative, then try Bodega. It's a pretty good app that allows user to download/buy apps that existed before the app store did. However, if that's not enough, you can always use different websites such as www.macupdate.com, www.iusethis.com etc.

Typically, the method that you described will work. However, in some (rare) cases, the app will change the way it stores settings and other information, and that would cause the old version to misbehave until you delete the app's settings (usually found in the Library folder) and start anew.

But, as far as the App Store goes, your method is pretty much the only way to go, and the App Store shouldn't complain if you reinstall the old version.