In the base game... is it really true that when the hero open a chest everyone gets that many conquest tokens and silver cards.

pacodub said:

Yes.

DJitD pg17
Money: Each hero gains the indicated amount of money, taking the money markers from the pile of unused money markers in the common play area. Copper/SIlver/Gold Treasure: Each hero draws one card from the copper/silver/gold treasure deck and may either keep it or immediately discard it and receive its money value (halved) instead. (In some chest multiple treasure cards are drawn, which indicates that each hero get multiple treasures)
Conquest Tokens: The heroes immediately gain the indicated number of conquest tokens (this is the hero group, not each hero individually).

Note that heroes do NOT have individual conquest tokens: there is a single pool of conquest shared by the entire party. So asking whether "everyone" gets the conquest is meaningless: that amount of conquest goes into the shared pool.

But each hero individually gets the treasures and coins in the chest. If you've got 4 heroes, and the chest says 2 copper treasures and 100 coins, then they each get 2 copper treasures and 100 coins (resulting in a total of 8 treasure cards being drawn and 400 coins being handed out).