I did call local water authority and they confirmed that meter is
buried below a cover in the front yard and that I have no BFP or
pressure reducer (at least installed by them.) So it sounds like I'll
just keep an eye on it (possibly mount gauge permanently near one of
the water heaters so I can see if it ever gets above 80 PSI) and not
worry about it too much.

Your biggest potential concern would be your washing machines inlet
valve. If this doesn't shut you'll flood the room. High pressures can
make these valves fail when they get older.