Thanks, Howard and Mark!!!!
While I had loaded the sheet in the front loader I had
NOT specified that in the "Page Setup" as "US Letter (Front Poster Board)".
Once that was done. I was able to go to "Printer Settings" and select "Watercolor Paper - Radiant White" as recommended by Breathing Color for this paper.
I guess I just got too anxious to print on the new paper and my brain short circuited.
Anyway, my initial impression is that this is a remarkable matte paper.