[bogie]

Okay - assuming that this doesn't go off the rails...

Is there a provision for a 30.06-type sign in the law?

[StLGlocker]

Yes. 571.094 20.

Buildings owned by the Guv'mint...

(6) The general assembly, supreme court, county or municipality may by rule, administrative regulation, or ordinance, prohibit or limit the carrying of concealed firearms by endorsement holders in that portion of a building owned, leased or controlled by that unit of government. Any portion of a building in which the carrying of concealed firearms is prohibited or limited shall be clearly identified by signs posted at the entrance to the restricted area.

and private property...

(15) Any private property whose owner has posted the premises as being off-limits to concealed firearms by means of one or more signs displayed in a conspicuous place of a minimum size of eleven inches by fourteen inches with the writing thereon in letters of not less than one inch. The owner, business or commercial lessee, manager of a private business enterprise, or any other organization, entity, or person may prohibit persons holding a concealed carry endorsement from carrying concealed firearms on the premises and may prohibit employees, not authorized by the employer, holding a concealed carry endorsement from carrying concealed firearms on the property of the employer. If the building or the premises are open to the public, the employer of the business enterprise shall post signs on or about the premises if carrying a concealed firearm is prohibited. Possession of a firearm in a vehicle on the premises shall not be a criminal offense so long as the firearm is not removed from the vehicle or brandished while the vehicle is on the premises. An employer may prohibit employees or other persons holding a concealed carry endorsement from carrying a concealed firearm in vehicles owned by the employer.

Notice that government buildings don't have any specific criteria for the signage, but private property signs must be 11X14" with 1" lettering.

[Frenchy]

You covered that nicely, StLGlocker.