Your stock map can be saved to your AP when you flash a new map. If your AP was stolen, its gone, unless you backed up the map. To do that, you must unhide the hidden partition on the AP and copy off the contents. Most people don't do this (its optional).
AP's are married to a car once you install a map/tune. If you plug in a friends AP, it will ask to install itself on the car. Easiest option would be to flash a stage 0 (stock map) to the car and uninstall/unmarry again. No need to send your ECU to Cobb, and no need to purchase a replacement AP.