Got shot of the Marigold Acnes, now I've got my fingers crossed!

My pal came up trumps with an unused Panaracer Smoke and a part worn Ritchley today. So now I have tyres which at least look like they can hack it! However, they both date back 4 years. The Panaracer was a little rigid which suggests it's past it's best. And the rubber flashing around the bead was like a razor, hopefully it won't puncture! The Ritchley was actually perishing! A quick inspection of my old bike shows the Panaracer Dart on it was in better condition than both tyres, in spite of it's 10 year or so vintage. So I now have 2 tyres that look the biz or are they about to disintegrate on me?