Definately one way to check for a loaded ML is to drop the ramrod the last 2" or so into the bore. If you get a clanging sound and, like Cayugad says, the ramrod all but disappears, it is unloaded. If the sound is more of a duller thud then there is a good possibility that there is something in the bore.
I guess that was why you were having so much trouble getting a burn mark on your patch when you fired the caps off earlier.
It is definately a good thing that you soaked the breach. It would have been tough to explain to the little lady why the house smells like sulfur and why there is a remrod stuck in the ceiling.
Thank God no one was injured and your mystery is solved.