The one's I am looking at certainly look official. I believe that what happens is they order from the same place - you are paying the agent to search for the certificate and do the ordering paperwork for you.
The ones I have here are quite old, but indicate they are certified copies of entries. If they can tell you the date, at the end of the day you could order the certificate from the BDM agency. Are you authorized to order the certificate though? Often, if it's a marriage after a certain date you have to be one of the people on the certificate or next of kin.