Weddingbee boards

My FI was born and baptized in Mexico, so he asked his godfather down there to get a new copy of his Catholic baptism certificate and mail it up here.  His godfather called today and said that they had asked whether he needed it for marriage or not, and if he needs it for marriage that they have to get a lot of his personal information first

What's the difference between getting a "marriage" baptism certificate versus "normal"?  Is there more information on the certificate that's required by the Catholic church or something?  Or do they just want to get his name down so he's not allowed to marry a second time in the Catholic church?

And does it really make a difference if our marriage is taking place in the States?

Thanks to anyone who can shed light on this!