They might, though I've seen breakers destroyed by interrupting less than their rated current. Well, the available fault current was calculated to be less.....
As sort of a side note, most manufacturers recommend replacing any breaker that has interrupted a fault-level current. Considering the intensity of the arc and the loud bang it makes, this is likely a good idea!
I've tested maybe a dozen or so breakers of all sizes that have interrupted fault-level current, not one has passed the fall-of-potential test. The contacts have been damaged beyond repair. Even if the breaker is cycled a bunch of times, there's still too much voltage drop across the contacts.
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