Flipflopman--thanks again. Yes inconel is the metal itself. What got me started on this question is a source I had at a museum who was researching the question and believed that different 'finishes' were called out in different versions of the same part with different part numbers, and that some of these were finishes were "metal coatings". Unfortunately he no longer works there and so our information has dried up.
Since I've never seen such a powdery-looking matte surface result from bead-blasting, I'm searching for information on what the process might have been.
The satin finish I could imagine to be just a bead-blast.