IH and IS. They were sitting in his safe for 6 years. Do you think they still might work?
If they have been kept in a dark place with reasonably stable temprature then they should probably be fine. The pheros themselves are pretty resilient and long lived.
What can happen though is that the more volatile scent components can suffer esp if the temp has gone high.
So give them a try and maybe use a cover scent as well. 
They are in an alcohol carrier and, just long as stored in a reasonably cool and dry place, will be fine for many years (just like Jack Daniels). I have a couple ancient bottles of Edge (2005?) and they are just as potent (& funky) as day one.