This is an official player badge from the 1980 Open Championship at Muirfield, which was won by Tom Watson. This badge purportedly belonged to Seve Ballesteros, who was defending Champion in 1980, and finished T19 at the 1980 Open. Seve's name is engraved on the reverse, though this was likely done at a later date to signify that it belonged to Seve. Since names are not engraved on thes ebadges and was done at a later time we can not say with any bit of accuracy that this was seve's badge.