The last chapter of Menger's Principles is dedicated to the problem of  
money. There he uses an expression like "naturgemaesses Product der  
menschlichen Wirthschaft" (natural process of human economy), but   
as far as I know, he does not seem to be using a phrase "spontane  
Ordnung" (spontaneous order). The same can be said of his next  
methodological work.  
  
Of course all of this does not deny that Menger was a source of Hayek's   
arguments together with various Scottish Enlightenment authors,   
including A. Smith.   
  
Anyway, "spontaneous" and "order" are   
bread and butter words in any western languages. I suppose that   
it was very easy for Hayek to coin the new (?) terminology "spontaneous  
order".   
  
Yukihiro Ikeda