If anyone is doing good things and thinking about ensuring a place in heaven I think it's not selfishness. Can you tell me why one people help others or gift others? One of the best possible answers is satisfaction. Whatever the reason, the result is the same.
Besides, I don't think only ensuring a place in heaven is the only reason behind helping others or giving gifts. It was the only reason then in this world the crime rate would not be so high because for criminal hell also exists.
Hmmm... you have a point though. In the end, it all boils down to who we are and what goes on in our minds.