You may want to think of it this way...
The treasure belonged to the TB party. When the property was sold, the treasure became the property of the new owner. This continue up to the current owner who now owns the treasure.
Your share is based on how much the owner will pay for your information. The more valuable you make your information the larger your share will be.
Once you convince the owner it's on his land he may try to dig it up with out you. So the question becomes...can he?
The next question is...how much will it cost them?
IOW, if your decoded message used a marker to locate the treasure that the owner can identify and dig, then there is a chance to be cut out.