Was Andy really 'free' in the end?

Yep, free.

Dufresne disappeared into parts unknown. Retired businessman Randall Stevens lived the good life.

At best, you can say that Ellis Redding's appearance in Zihuatanejo might put him in jeopardy, but I doubt Red would pose a threat to Mr. Steven's true identity.

Didnt look too terrified to me.

He looked happy, rich, reunited with his friend that he didnt know he'd ever see again, and on a beach in Mexico.

He's feeling just fine.