If one tries to create a folder in Windows Explorer which ends in "." ( like "company inc." for example) then Windows will truncate the "." for compatibility.
The same happens if you create a space in Alfresco via CIFS, predictably.
You can, however, create a space name in the web client with a trailing "." and when you try to access it via CIFS, you get the Windows error: "…refers to a location that is unavailable…yada yada"
I hit this today working at a law firm that set up a space name ending in "Inc." Seems like the trailing punctuation needs to be validated for CIFS compatibility.