I searched and searched and from research I did read about a batch of 'dodgy' ones from China which had a much recent manufacturing date on them - although aparently they stopped making them years ago.  I'm trying to find the relevant thread for you....

I may have a local option with some s/h ones...Will get back to you soonish...

Ed from GPE used to stock them, but I believe he might have been the person that found some of the counterfeit chips.