OK, here we go.
Buy this coin ten times out of ten for $50. Here's why.
I see no reason to doubt the authenticity. Indeed, certain features make it very difficult indeed to counterfeit. However, it's damaged and that's what I'll discuss first. On the obverse, note the ding on the rim at 4:00, and those patchy round cleaner areas in that vicinity. Also note the faint horizontal striations across the cheek from where someone probably attempted to clean the coin. At Noon - the very top - you see a flat spot caused by a hard hit. On the reverse, above "In God we trust" you can see the scratches someone put onto it.
All of these combine to create a very damaged coin, one we refer to as a "Details" coin because the damage causes you to offer a technical grade - what the amount of wear detail alone is worth for a grade. But it's not original, having been damaged, which is prized in numismatics. The surfaces have been altered through cleaning, scratching and damage. Therefore if I call this coin VG Details (I am), the details are VG but the value may only be that of a AG-G coin.
That was the bad news.
The good news is,
Morgan dollars are collected by variety - they're called VAMs after the two men who originated the system - and this is a
good one. It's VAM-3, Capped Die "Large over Small CC" variety. It's so popular that it was named to the Top 100, the very first list of extraordinary collectable VAMs. You saw the proof yourself (good eye) - the mint mark.
You cannot afford this coin in better shape. If it weren't a Details coin, it'd be worth $150 in that grade.
Now, the (important) caveat is that I'm working from imperfect online images. But there are very few 1879-CC varieties, the look of the mint mark is characteristic - and impossible to counterfeit - and I would
absolutely pull $50 out of my pocket right now for this coin. I would take the chance based on what I see here.
That's my opinion, I am admittedly optimistic but I'm also fairly good with Morgans and I like my chances of being right. You also have the time to await more opinion.