Ilithian

I've finally figured out this problem! I was having the same issue and after a bit of research, got it to work.

You need to edit a plist file that has somehow retained your old machine's identifier and edit that information out. Here are the steps: 
Open the following file with a plist editor of your choice (Xcode, PlistEdit Pro, etc):  ~/Library/Preferences/com.apple.SystemProfiler.plist Under the 'CPU Names' field, locate the identifier for your current system as well as the identifier for your previous system. Delete that old identifier. Save the plist file. In Alfred, reset the About workflow by typing the keyword:  xabout When you run the workflow again by typing the keyword 'about', you should now see the correct 'System (Model Identifier)' entry!