Where to find Informaciones Matrimoniales?

Hello

I was hoping to find an Informacion Matrimonial for my forebears, Manuel Romo and Maria Ygnacia Rodrigues, who got married in Nadadores (Coahuila) in 1816. I have not been able to locate them in Family Search...In a previous post, another member (George Fulton) mentioned that there were no informaciones matrimoniales for Coahuila (which was under Monterrey) before 1888. Or are they just filed in another archdiocese? Or were they just not required for everyone? Are they in the archives but just not online (I think that's what George meant?)

A more general question:
Do these petitions always get filed where the marriage takes place, or always where the bride lives, or always where the groom lives?(Manuel was originally from Aguascalientes).

Regards
Denise Fastrup