A certified copy is something you ask for, usually after the fact. You "order it". However, I have a certified copy of my Texas Divorce decree, that I carried out of the courtroom. Actually three certified copies. That you have a paper with a stamp may or may not be a certified copy. For Texas, it is the entire decree, usually multiple pages. It will say on it's face that it is a certified copy. Is that what the stamp says? Please describe the stamp and exactly its wording.
Edit: I do see the stamp on the page in your first post. It does not indicate anything about it being a certified copy. I cannot tell if all the pages are there. I don't see any signatures.