Omega speedmaster professional racing advice needed

Hi all require some advice on this speedmaster professional..got this given off my dad years ago before he past away. He was abit of a character do not sure if it's real.. he told me to keep it and use it but was always unsure of the value and did not want to loose it..however I did start to use it and the pin on the strap came out but luckily I noticed that and never used it again..what I need to know is if it's the real deal or fake..if it's fake then I can wear it still with pride but not having the worry of losing it.Have some pic to look at