system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How are dice fair?

Shouldn't 6 appear more often because it has the most amount of holes and has a lighter weight than all the other sides?
gpt
Casino dice have the holes filled in with a contrasting color so no weight difference.  They're also clear/translucent so the players can see no weights inside the dice.  

The stamped dice you're referring to are going to be "close enough."  Technically head/tails are likely a little different too but it won't be enough to matter.  As far as the physics behind the stamped dice, the 1 will have the least amount of material removed and would therefore be the heaviest which would put it the least common roll.