Sorry to inform you that it is NOT the lock in question.
Master # 536KADPF is a 4 Pin, the lock you found is a 5 Pin, also the body looks to have a bevel on the Top which my lock does not.
It is my understanding that the Master Product Code of 5xx indicates that it is a 5 pin lock not a 4. This only serves to compound the level of suspicion attached to this derned thing.
This gets mysteriouser and mysteriouser don't it ?
I see from your profile that you live in TO. My father was a Newfie and we owned an Island in Georgian Bay (up the Key River), also a Cabin in Haliburton Provincial Park (near Elephant Lake). I live in Rochester, NY now (just across the lake). Are you an Amateur Radio Operator [ham] by any chance ?, my callsign is N2TFG.