Any Chance This Morgan Is An Impaired Proof?

After many months, I finally had the chance to go through some of my father's coin collection today that has been in the hands of my brother since my father passed away last August. Tons and tons (well, pounds and pounds) of junk silver including very worn Barber half dollars and Walking Liberty half dollars, mostly worn and halfway decent Franklin half dollars and silver Kennedy half dollars, extremely worn Mercury dimes, decent condition silver Washington quarters, etc. Plus a ton of other stuff, including mint proof sets, modern commemorative coins, a prestige set or two. Oh, and lots and lots and lots of Lincoln cents from the 1920s up to the 1960s.

Anyway, nothing really exciting from a numismatic perspective, but a lot of fun to look through and I did end up buying some of the junk silver off my brother, who would rather have some spendable cash than have to deal with trying to sell the coins on ebay or to a dealer (and yes, I was generous with what I offered him).

One coin, though, caught my eye. It was an 1879 Morgan dollar in a bezel. Very dark, but still in nice condition, and when the light hits it just right a lot of colors shine through. I've never seen toning quite like this before, and there's something about the fields that makes me wonder if it could possibly be an impaired proof. Probably not, I know, but I figured I'd share it with you and get your opinion. Sadly, although I actually own an actual proof Morgan dollar, I am not familiar with the diagnostics beyond the mirror fields.

And so, without further ado: