"properly stored and was still soft. "
....sorry Barry, but what is "soft".....old tyres are simply that, old tyres.
...I was once a fast type rider (Honda sponsored), we would ONLY use a brand new tyre, there is an enormous difference between old and new rubber on the track, so i guess the same must apply to road tyres....if you have the choice, buy new rubber....the compounds will be different anyhow with older versions, they only get better with new ones......