[Salvation]

No it isn't. Each Catholic bishop or archbishop can denote one parish for a Catholic Latin Mass. Whether he does it or not is his doing. But it is not prohibited by Rome.

Requests for Indults (Latin Masses) go in to Rome all the time.

[RaginCajunTrad]

More than one parish in a diocese can be designated for an Indult Mass. The bishop, in theory, could give all the priests in the diocese permission to pray the Traditional Mass any time they desire. No bishops do. Most bishops are recalcitrant in that matter and restrict the Indult Masses to one parish in the diocese one day a week often at odd times. Some bishops won't allow it at all.