The flatness of the look can be a sign of cleaning. Harshly cleaned and scrubbed you can see streaks in the coin in the same direction (that aren't die polish lines, but scratches.) When copper is cleaned it will be pink or orange.
As coins are minted "flow lines" begin to appear from the heating of the dies as they lift off the planchets. Those are most visible in planchets struck on older dies that are deteriorating, and the coins will sparkle like a diamond for it. When you don't see that, which is a "cartwheel" reflection, it's a sign the lines were disturbed by a harsh rub or cleaning. The surface will appear flat for it, lusterless, dead. There's the first thing that goes, the flow lines. A polish or buffing will not replace those flow lines, as they were caused by the hot dies lifting off the planchets. As such, you clean a coin, you just did irreversible damage to it. It's all in the reflection, how the coins reflect the light.
Luster, specifically cartwheel luster, has nothing to do with hot dies lifting off the planchet. The luster is created by microscopic flowlines in the surface of the die created by the radial movement of the planchet metal during striking, brand-new dies show no cartwheel luster and as the dies were used it begins to appear and become stronger until you reach the point that the flowlines in the surface of the die are heavy enough to become visible to the naked eye, at which point the surfaces of the coin start to appear eroded rather than lustrous.
I beg to differ. The colder the dies, the less the displacement. That's why you get the proof-likes, in the beginning, even though the striking pressure, even though the radial force imparted, is the same. As the dies heat, the more the metal is radially displaced, i.e., outward from the center, in the softer planchets. As the heated dies lift, they take some of that metal, leaving the "radial flow lines" on the planchet. If that were not the case, there would be flow lines in the colder, "first strikes," as well. Rather, those have a glassy, proof-like appearance, and obvious absence of the flow lines. Think about it. Evidently, you hadn't.
To everyone you don't know how much I appreciate your comments. This is a great forum!!!! I am old but not to old to learn. I am enjoying learning about coins. I had no idea there was so much to learn but I love a challenge.