The article doesn’t mention the weight of either side of the coin at all, though. Even a blank planchet will land with the same side facing up as when flipped 1% more often.

“From the moment a coin is launched into the air, its entire trajectory—including whether it lands on heads or tails—can be calculated by the laws of mechanics. The researchers determined that airborne coins don't turn around their symmetrical axis; instead they tend to wobble off-center, which causes them to spend a little more time aloft with their initial “up” side on top.”

While the distribution of the weight of a coin certainly makes a difference (heavier side down more often) the observations made in the study are new.