JP Sauer and Sohn .357 chief marshal

Question
I recently purchased this gun from a family friend and he says he has had it since the late sixties the serial number is 0551/6 I was basically just wondering what year it was it seems like a very good shooter outside of screws that loosen up from shooting it several times.  I was also wondering if I can put anything on them to keep them tight. Thank you for your time it is greatly appreciated

Answer
Hello Erik. Your Chief Marshal was imported from Germany by Hawes Firearms in 1969. As for the screws loosening up, I have used the thread sealer 'Loctite' when mounting scopes. It works even under severe recoil. There are three grades. Green for 'permanent hold', Red for less hold (still too permanent for small screws), and Blue for 'tight hold'. The Blue would be all you need for those screws and you can still remove them with a proper fitting screwdriver. I hope this answers your questions and thank you for asking for me. Charles Gage