Small plot hole ?

Have watched this movie several times. Came up with 2 unexplained questions. Can anyone help?

1. The piano with the sceptre in the leg was shipped from France to Montreal, where it was impounded for insect infestation. We're not told anything about the owner and whether or not he knew the sceptre was hidden in the leg. He certainly would have been informed about the impounding and subsequent burning of his piano. He doesn't show up to rescue the hidden treasure, so isn't it clear he didn't know about it? This leads to question #2.

2. Jack (Edward Norton) is a small-time heister. He comes out of nowhere, and gets himself hired at the Customs House because of this one score. And he somehow makes sure he's present when they start to burn the piano legs. That's a trick in itself. But the real question is....how does this small-time drifter know the sceptre is hidden in the piano leg when nobody else on the planet seems to know it?