Sir is an honorific address used in a number of situations in many anglophone cultures. The term can be used as a formal prefix, especially in the Commonwealth, for males who have been given certain honours or titles (such as knights and baronets), where usage is strictly governed by law and custom.

Based on that paragraph can we conclude that this sentence is true?
Sir is used for men titled knights of orders of chivalry, where usage is strictly governed by law and custom.
It's impossible to say