Only if the Wedding Mass is celebrated at the Sunday liturgy would this fulfill the Sunday obligation. If the Mass is celebrated at another time, it does not fulfill the Sunday obligation. Masses on Saturday to fulfill the obligation for Sunday begin at the earliest 4 PM and would use the Mass of the day (readings and prayers) for the Sunday or Solemnity (Holy Day) with the Rite of Marriage included with the nuptial blessing. (Rite of Marriage #11)
For example, if a wedding liturgy is celebrated at 2 PM on Saturday, it therefore would not fulfill the time requirement to celebrate the liturgy for Sunday and the readings would be taken from the Liturgy for Marriage.