M.Werner original??

This was left to my wife when her mother passed away. Her mother bought it app. 50 years ago. It is signed M.Werner. Does anyone know if there is a way to know for sure if it is an original. I am certainly no art expert. I dont want to hang a "copy" on the wall. Its app. 3.5 ft. by 4 ft. She was a multi-millionaire and I find it hard to believe she would buy a "copy",but I just dont honestly know! Thank you!