Top and bottom, yes. I'm waiting for mine to crack as the are the ones I bought years ago. I do have new ones waiting.
At one time Sizzix sold some shims for embossing. If you can find, might work with Accuquilt dies. They are silicone rubber. I still have one from cardmaking, along with the adjustable platform.
http://www.sizzix.com/product/655121...ilicone-rubber