From the pix, it looks more like aluminum than stainless to me.
Hi Chuck,
It appears to be stainless, I scratched the inside of the frame with a very sharp SS kitchen knife and it barely scratched the surface. It just has that semi-dull brushed finish that's so popular on aluminum.
Even if I could hot blue it, I dislike hot-blued frames nearly as much as what I already have. It's just not worth it to me.
BTW, I resculpted the forend, before it grabbed you by the throat and shouted "I'm a machine made BEAVERTAIL forend, and damn proud of it!" Hopefully that look is gone, it's still a beavertail, just not so beefy.

Original BEAVERTAIL forend

After resculpting, Ive only put on one coat of linseed oil so far
Steve
Steve