I did it not too long ago.
I was not able to get it in Chrome today, but it did appear from examining the source code of the final checkout page that the offer is still there. I just don't know how to decipher the HTML code enough to determine what to do to get the offer.
If you are a Costco Executive member, looking for two boxes of the cheapest duplicate checks, Costco has the better deal.
With 4Checks, you get 250 duplicate checks for $9.95. With Costco, you get 350 duplicate checks for $11.53.