OS X Mavericks :: Automator Batch Rename - Removing Type Of File With No Extension

I've set up an Automator to batch rename files. The renaming works fine. The problem arises when it renames a file which doesn't contain it's extension (a common MacOS practice). Is there some way to make sure it preserves the filetype? For instance, this works fine: 

Original:

Output:

 And this results in an error: 

Original:

Output (file type has been replaced with generic "document" type)

Automator logic, can be viewed here.