I am all but certain that National Sports Photos was affiliated with National, a New York photo company that was one of the three big studios that shot publicity photos for boxers and entertainers (with Apeda and Cosmopolitan). Here is a Marciano publicity photo by National:
Same approximate era and style.
My theory is that NSP was National cashing in on its image archive.
But I digress...
I see no reason to grade photos unless you plan to sell. They are a PITA to store and very costly to slab. I will buy an exceptional one but prefer not to do it for my PC. When I sell, or when my daughter sells, I assume they will end up slabbed. Until then, they stay in mylar in albums
