Retired: 2015
GUARDIAN LION (Special Edition) Lladró

How can I tell if it is a new item, or if it was previously owned?

There is no way to tell. By definition, most "retired" collectibles of any kind are previously owned unless they're dealer stock. "Active" production is sold by Authorized Dealers and "discontinued" production is sold in the secondary market by collectors. As a practical matter, newer retirements are probably discontinued dealer stock. However, the older, more valuable pieces, are rarely dealer stock.