If a record is re-indexed with the same objectID, the events that were associated with that record will still be relevant and will be 'reconnected' to that record.
This is because Algolia's Analytics and most AI features (such as Dynamic Re-Ranking) only use objectID to identify a record. The data is collected on a separate server and is considered a separate entity to an index and its records. Therefore if the data associated with an objectID disappears (deleted record), or changes (record update), this will have no impact on the reporting by the Analytics API.
You can read more on how Analytics Data is stored here.