I'm not sure what the question is.
Mint set coins made since 1965 are struck at higher pressure with new dies and more carefully handled. This pretty much assures almost all coins are nicely made and nicely struck but mint set coins can be scratched up. Most have marking.
To see a coin in mint cello just squeeze the edge through the plastic with your nails and the scratches on the plastic don't move with the coin.
Most sellers of mint set coins will probably remove the worst coins since these would be bad for business. But they'll also remove the finest coins since these will bring a higher price. In other words typically the coins you get wuill be better than average but there will be no gems.
Time don't fly, it bounds and leaps.