Here;s a pic of the couch itself.

This law label only refers what is inside the sofa, in other words the soft filling.
Leather has a suede backside.

Chateau D'Ax is leather, but I don't think it is high quality leather. Some of it may be bicast leather which is split hide that is essentially painted/embossed with a top coat that has polyurethane in it. It is an animal hide underneath, but heavily processed. You are not allowed to call this leather in some countries.

Or it could be corrected grain leather, which is inferior hides that are sanded and embossed and dyed.

It's not a full grain (the highest quality),

A new full-sized Chateau D'Ax sofa at Raymour and Flannigan sells for $1100. One of them says Bicast in the description, the other says 100% leather. But they are the same price.

If it is indeed Bicast leather, yes in the US it is leather, in Canada it is "leather and polyurethane" and in some countries, no, it isn't leather.

Depending on how much they are asking and how well it seems to be holding up for it's age, when you examine it, it still could be a reasonable purchase.