What a joke. Those rings are not for sale to the general public at Yankee Stadium kiosks.
No, but the New York Yankees (and almost every single sports team) usually allows for certain "select" individuals not employed by the team to purchase rings (they grant permission to the company that makes the rings, rarely do they actually buy them for the said individual).
Generally, its up to the owners discretion.
Famous story, after the Dallas Cowboys won their first superbowl under Jimmy Johnson, they did actually purchase a ring for Al Davis of the Raiders and presented it to him. 2 versions of why, came from Jones and Johnson. One is a positive (Jones), one is a negative (Johnson).