Hello Madera,

No, the King did not visit Sobrerete, because no Spanish Monarch ever visited the Americas prior to their independence in the 19th century. In the 1680s, the King of Spain was Charles II (and last of the Hapsburg monarchs of Spain) But it was his prerogative to give and confirm political/judicial appointments. It was also customary before the French Revolution for European rulers to use their name, speak of themselves in the first person plural, and assert that they ruled by the Grace of God.

The document won't open for me, but usually all such documents if written at Court would start something like this:
"We, Charles, by the Grace of God, King of Castile, Aragon, Count of Barcelona, Emperor of the West Indies, etc. do confirm D. ____ in the office of ____."

In Spanish is would be:
"Nos, Carlos, de la Gracia de Dios, Rey de Castilla, Aragón, Conde de Barcelona, Emperador de la Indias Occidentals, etc. confirmamos a D. _______ en el oficio de ______."

Hope that helps!

Sean