So, you never mentioned WHY you need to replace this module?
You did tell us that you have "2012 f350 king ranch with factory nav" - well, the reason you cannot find the GPSM is that your truck DOES NOT HAVE THAT MODULE. Ironically trucks without navigation do have this module as it provides vehicle location for real-time traffic reports and re-routing, and for identifying vehicle location in the event of a collision. Your factory navigation system is incorporated into the ACM (audio control module) and uses a dual GPS/SDRS antenna located on the roof.
Sooo, with that said, you are looking for a module that does not exist in your truck. Relist your module on eBay.
Some scan tools - event the Ford IDS will list all possible modules the truck could have. For example, if I perform a network test - "optional modules" will show and failing if not present. You kinda have to know whether it's there or not... What sucks is that you spent a few days hunting for a module the truck does not have. Navigation related codes will be in the ACM (audio control module) and the APIM (accessory protocol interface module) as well as inputs from several other modules by way of the MS-CAN network.