Phrase in death record

Not necessarily. It was probably just a legal formality, in case the spouse wanted to remarry. Coincidentally, I was just transcribing a marriage investigation that got snagged, because the husband was from Spain, and had been married previously, and he needed to provide proof that he was "libre de matrimonio," and had unfortunately lost a signed affidavit from his home parish, confirming his first wife's death. 

Have you found the couple's marriage record? Another way to see whether they were legitimately married is to look at the baptism/birth records, and see if it says the child was legitimate.

Saludos!

Manny Díez Hermosillo