That is excellent advice. Find someone who does upholstery for a living, and has a track record. Ask for references from some of his former customers. Any good upholsterer will be happy to furnish references. Then go look at the work that was done.
There are a lot of guys who claim to be upholsterers that you should stay away from. When it comes to upholstery, "good" and "cheap" are never the same. Good luck.