The last time I had a Guinness was March 17th. It tasted just fine & there was a widget in every can.
BTW, I always enjoy a “Black & Tan” on St. Paddy's Day. Simply fill the glass half way with a light ale (Bass Ale is best for the symbolism). Then carefully pour Guinness over top — use a spoon bent back to break the fall of the Guinness, so it stays on top. (Heat a cheap plastic spoon handle a bit, then bend it back, so that the convex side is up.)
Drinking Black and Tans will get you killed in some parts of Ireland. I’m not kidding. Black and Tans are the drink of the Orange Royal Irish Constabulary and mostly detested in the Republic.