We have done several driver side outside key locks on the 47-51 and I do not believe a slim jim would work. If the designers of the AD door latches were still alive they should be sent to prison. Once open I wouldn't close them again till they had bear claw latches (Trique Latch). Many an AD door has popped open while underway so the very minimum needed for kids is a good seat belt. The picture shows your type latch. On the right side is a part with a series of notches in it and just above it is a lever (pawl)that is bent at a right angle which drops into a notch to latch. There's really no way for a slim jim to hook under the pawl to release it. Wouldn't you know it, you asked the time and got the history of clock making.
http://s32.photobucket.com/user/coilover/media/doorlock004.jpg.html
