Greetings Mojjax, Are you familiar with the concept of the "night watchman". The night watchman kept watch in or around a building or factory. He walked a route, station to station that required him to trigger a time stamp at each station. He had his own dedicated key that fit one of several holes in the timeclock. As he walked his route he left a record of being there by activating the timeclock with his key. This was likely a fob that went with his key which might be the one under the "Makin Bacon" fob. That key may not be unique enough because they were so complex that no one could have copied it readily.
Best wishes!