I noticed that none of the treaties dealt with the ownership of forts located in Mexico not held by the U.S. Do you suppose that ownership of property within their borders was assumed and agreed to by both parties to the treaty? But regardless of who held posession, ownership was agreed to by both sides as indicated by their signature on a treaty. It was not arbitrary and one sided.
In other words, what was on the ground within their own boundaries belonged to the respective countries.