My question is in regards to import code letters- those three letters found on the balance cock of Swiss watches. The letters for Patek Phillipe are PXP and only PXP as far as I know. I have recently evaluated a genuine Patek that has some condition issues. The brightest bridge on the mov't(cal. 9,no.90) is the balance cock and it bears the code "HOX". I am puzzled as to how a perfect replacement balance cock, with correct regulator spring, correct demascene etc., could end up on the Patek ebauche? Was this not an exclusive Patek ebauche?? Any idea who "HOX"is? ? ?
My thanks for any help.