Upon the occurrence of divorce, should one consider the dower mentioned in the initial, unproven marital contract, or the dower subsequently established in the Sharia court to settle the wife's rights and the issue of the dower?

The binding mahr (dowry) is that which was agreed upon at the time of the marriage contract, whether it was documented or not. Documentation is a confirmation of the initial contract, not a condition for its validity, but it is preferable to avoid disputes. If a dispute arises regarding the additional amount documented by the bride's guardian, the Sharia court should be consulted, as a judge's ruling is binding and resolves disagreements.