A 1950 model is not required to have turn signals, but you must roll the window and point to the left for a left turn and point up for a right turn. However, very few people will know what you are doing. Turn signals are only required on 1960 or newer models that are less than 80" wide.
http://www.txdps.state.tx.us/rsd/vi/publications/rules/safety_manual/chapter4.pdf