In the automotive world......
So far, more than 100 deaths have been attributed to old tires, and there is currently a lawsuit against Bridgestone/Firestone for selling old tires as new. It’s alleged that these tires were responsible for a crash which left one man dead and a family without a father.
And yet despite all of this evidence, the National Highway Traffic Safety Administration (NHTSA) has refused to impose a six-year shelf life on tires. All they have issued is a warning . Why? We could speculate, but money talks, and how many tire companies are ready to junk thousands of tires every month that could easily be sold as new?
Most tire manufacturer's warranties cover their tires for four years from the date of purchase or five years from the week the tires were manufactured. So if you purchase new tires that were manufactured exactly two years ago they will be covered for a total of six years (four years from the date of purchase) as long as you have your receipt. If you lose your receipt, your tires' warranty coverage will end five years from the week the tire was produced (resulting in the tire manufacturer's warranty coverage ending only three years from the date of purchase in this example.
The quotes above are from the following link
http://www.wisebread.com/are-your-new-t ... time-bombs
That being said there is no question in my mind that motorcycle tires don't have the scrutiny and attention that DOT pays to the automotive counterparts, due to the significant lesser numbers.
Personally and based on my experience I would not have an issue with a tire that was made the 27th week of 2007, unless there were obvious visible signs (albeit there are other aging signs that are invisible). Aside from that, there is another thing that makes installation difficult and that is if the tires have been stacked one on top of the other (no-no) as that makes the tire take a set and it is a beach to get the beads to come in contact with the rim while airing them up.
In closing, it's really up to you, if you don't feel the tires are safe call the vendor and ask them to get you some fresher tires,(although you really don't have any legal bais for the request) be prepared to agree with them on how old a tire will you accept. I do agree that there are some really old tires in the warehouses, so it's best to ask the questions before the tire purchase. The one goodthing with our sizes is that the front is just about the standard size, the rear being a 170 v.s. a 180 is not as common.
Best of luck to you and let us know what is the outcome as it would be good information for this forum.
and the idea of a hardened tire frightens me. I have not had a good scare yet and would prefer to keep it that way. 
Thanks for the replies. I really did not cherish the idea of shipping a tire back. Already installed the rear and will do the front this week.