When I replaced my chain plates I was always disappointed that I didn't go the next thickness, you might consider doing that, if you went with 316 going a little thicker would make it stronger than the original.

The second thing is 'mirror polish them,

We had Garhauer make ours. You send them one of the old ones and they send you new beautiful ones. Reasonably priced as well.

Don't forget the forward head stay chain plate. It will probably be different.