You are right. I left electronic "tech"ing a lot of years ago. (CMOS was still new) Memory is a little rusty. Getting back into it is a major part of the appeal of model railroading. I must have been thinking about the protection for CMOS inputs where two diodes are connected to both power connections to prevent the input from going above the positive or below ground. Output protection diodes, like this picture from the L239 data sheet, are connected parallel to the load (coil).