Honestly, it's hard to tell from the top, unless the top has been beaten to utter oblivion, which is telling that it's a cast iron face. That one could either be a hardened face or just an under/barely used cast iron face. It's easiest to tell from the side of the face - does it look like there is a separate plate that is attached to the face or is it just a single piece with the top machined?
At any rate, are you looking to buy it, sell it, or just curious? If you're looking to sell it, PM me, I may be interested as I've been wanting a little feller to put on my desk at work.