I had a couple of pints of 3-M Diamont mixed up for me last week.
When I opened the cans, they look pretty well mixed except the black swirl in there. I spent 5 minutes on it with a stirring stick and can't get this black swirl to mix in fully. I don't have a paint shaking machine. I have a drill with a small paddle mixer, but I didn't use it (should I have).

Is this paint mixed thoroughly or not?

paint mixing by [url=https://www.flickr.com/photos/152383962@N02/]

As long as you got any sediment mixed back in you should be good to go. 5 minutes with a stir stick is more than enough.

My standox paints always looks like that in the can or spraycup. Never had a problem with that once spraying.

I would put it in a Shaker you can take it to any paint shop and they will shake it for you or use your drill with the Stir stick.

When properly mixed No you will not see that.

I Shake all my stuff even my Fillers before use

I use a bag system in my paint gun cup so I can keep shaking those
hard metallic paints while I'm painting.

Metallic colors almost always have that look.