I believe that sometimes we should not take what we dreamed about gambling serious because a dream comes base on what you have at heart before you sleep.
But sometimes dreams happen in reality whether in the games or in other areas of life, I think we know the dream story of Joseph in the bible.
Regards to having games in dream, it does happen too but I don't think it does often and sometimes it is not clear enough but you only have to analyse the way it was shown to you in that dream before you can finally arrive at the real numbers, although some happen like it was given in the dream.
Yes I have seen some people give testimonies of how they got games revealed to them in the dream, and some refuse to gamble it because of doubt but at the end it is real numbers, this happens is football betting. So getting revelation of games in the dream is still possible but may not be frequent.