Step 1: List what each wrong label forbids.
Label on chest 1 is "GOLD", so chest 1 $\neq$ gold.
Label on chest 2 is "SILVER", so chest 2 $\neq$ silver.
Label on chest 3 is "GOLD OR SILVER", so chest 3 $\neq$ gold and chest 3 $\neq$ silver.
Step 2: Narrow chest 3 first, since it has two restrictions.
Chest 3 cannot be gold and cannot be silver, and the only three possible contents are gold, silver and bronze. That leaves exactly one option for chest 3: bronze.
Step 3: Fill in the rest by elimination.
Bronze is now used up by chest 3, so chest 1 and chest 2 must split gold and silver between them.
Chest 1 cannot be gold, so chest 1 must be silver, which leaves chest 2 as gold, and this also agrees with chest 2's own restriction, since chest 2 $\neq$ silver, and gold fits fine.
Step 4: Check the whole assignment is self-consistent.
Chest 1 = silver (label said gold, wrong, correct), chest 2 = gold (label said silver, wrong, correct), chest 3 = bronze (label said gold or silver, wrong, correct). Every condition of the puzzle checks out with no contradiction, and this is the only assignment that works.
Final Answer:
Since one unique solution falls out just from the fact that all three labels are wrong, no chest needs to be physically opened.
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