Yes, the current sequence numbers are stored in a SAS dataset "MAMisc.Sequence" MAMisc library is stored somewhere down the line from sasconfig/Lev1/Applications/..., (the actual path changes with versions) and often times it is pre-assigned in your EG sessions (not always though).
It's the only place these numbers need to be updated, and in my opinion, it's relatively safe to do so. We have done such update from time to time (often it is needed when some migration is happening to avoid IDs overlapping).
Make sure you don't screw up this dataset encoding (prefer in-place updates, try not to "rewrite" it completely unless you're certain there is no encoding mismatch) and don't leave it open in your EG session after the change - it will lock the dataset and you will be getting an error in SAS CI Studio doing things like campaign creation, runs, saves etc.
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Dmitriy Alergant, Tier One Analytics