Is it important?
It's very rarely done. So in a way, no.
But if a large amount of engine wear happens during the first X miles (compared to the same 1,000 miles from say, 20,000 to 21,000 miles), it's not a bad idea to get fresh oil in there.
The manufacturer's recommendations and manual are...
"Walmart" oil (Supertech) is only $3.59/qt for full synthetic.
You wouldn't buy any of these oils that are all less than $30 for a 5 quart jug, and better than Motocraft?
The same generic recommendation for every driver and every vehicle they make.
Just like they used to recommend thinner 5W-20 oil but they don't anymore.
Also, the engine breaks in differently than say, the transmission, the rear differential, brake pads/rotors....
If you put new differential...
If you listen to podcasts etc where they talk to engine builders, the piston rings these days are so different than the old ones, they don't wear-in like the old days and they break in very, very quickly by comparison.
Okay, it's not steel or iron then. But aluminum, copper, etc are bearing materials and won't stick. I'd keep driving it for a bit and see what it looks like in a few hundred miles.
Can you get a small screen or cloth and try to get the glitter out of the oil and maybe rinse the oil away with...