What an interesting piece!...I would agree with Bill...Central or South Indian, and yes call it a sang if you like. Isn't the decoration strange though, similar to decoration seen on good Algerian Flyssa Swords.
Here is a very different South Indian Sang from the Armoury of Mysore. Note the similarities in the butt piece.
Somebody onec claimed that my example is from Ceylon, it is obviously not (mysore inscription). However, does anybody have any knowledge of Sangs from Ceylon?
Regards,
Runjeet.