Matte finish helmet - Problem?

[boy in a kilt]

I usually go off the manufacturing date stamp on the inside of the helmet. The helmet in question states it was made in March of 05(it had set on a shelf at the LBS for a couple of years). Given snell's advice of replacing every 5 years and the manufacturer's of every 2, I usually shoot for 3-5. So, it about due for one.
I usually cut the straps out of one I throw away, especially the crashed ones

That's pretty much the right thing to do in all cases. In the construction industry, you can be fined if the manufactured date on your hard hat is more than about 5 years ago, regardless of when you got the helmet.