I acquired a NY Standard 18S 4th model number 160799 and would like to date it. I realize records are destroyed, so if I could get an educated guess from someone who might have an idea, it would be appreciated. I did a search and didn't find anything. It is running well and from what I did find in searching, it is a bear to reassemble. I'm wondering if I should leave it alone. I have this thing about tearing apart every watch I get to clean and oil it...