I am still learning myself. Yes, unfired clay bricks are what I used - 435 so far and I need about 90 more to finish the other batter's box. In all of the reading I did and the little bit of repair work I have done with mound clay, this seemed like the best way to go. Based on how many times some of them had to be reset to get everything right, I now know working with bagged clay would have been tougher.
Thanks for your comments.