Get a Malibu GM certified after purchase?

I keep hearing about GM certified vehicles - can you take a qualifying vehicle to a dealer that certifies them to get them GM certified. We have a 2004 Malibu with 48,000 miles on it and we asked our dealer when we purchased the car, and he said he wasn't a certified GM dealer, he said even if he was - we'd have to purchase an extended warranty to get that? Is that correct? My daughter has a friend who sells extended warranties and he thought we could still take the car to a GM certified dealer and for a fee - get it certified to get the additional 100,000 warranty. And what does GM certified even mean - what's covered under that? Is it worth looking into?

Only a Certified GM dealer can certify a vehicle BEFORE purchase. There is no way to bring it back to be certified.

Certification includes a 3 day/150 mile return policy.