How did you get that from k-mart? did you ask them to check the FW or something?
LOL no, you can do this magic thing called "return" as long as the product doesn't seem opened (of which i've done numerous times) so if the firmware was above 3.55 I would have put the box back together, took it back and waited a few days then bought another. It's just a matter of luck really and I did this in one try. Just buy it from a not-as-shopped at retailer and you should be good. Lots of old PS3s in stock.