Arrieta makes fantastic sidelocks, regardless of who imports them. You have nothing to worry about in the quality department. But I would find another one for the price being asked. Like Doverham said, Orvis has a couple used ones for less.
Here's a nice upland model w/ 27" bbls. $3300
http://www.orvis.com/intro.aspx?dir_id=1089&group_id=25577&cat_id=15480&subject=8062This one would be ideal for clays, dove, or waterfowl with its 30" bbls, rounded Prince-of-Wales grip, and semi-beavertail forend. It's also $3300
http://www.orvis.com/intro.aspx?dir_id=1089&group_id=25577&cat_id=15480&subject=7951Adam
