Correct.
How many cities do you know of that don't adhere to those guidelines though? Just to appease you I looked up the city ordnance in Garland that prohibits the use of BB guns in city limits in this case. If he were to miss the target and have the BB fly over the roof it would be in violation. The ordnance also states that the exceptions are only to defend the person charged, it is not allowing it.
Sec. 26.05 Projecting of missiles prohibited
(A) No person may discharge a firearm, rifle, shotgun, automatic rifle, revolver, pistol or other weapon designed for the purpose of firing or discharging a shell, missile or cartridge, whether the shell, missile or cartridge is blank or live ammunition, in any place in the City.
(B) It is a defense to prosecution under this section that:
(1) The person was a peace officer or animal control officer acting in the performance of his official duties;
(2) The person was at a shooting range operated by an agency of the United States government, the state or a political subdivision of the state;
(3) The person was at a privately owned shooting range which had been approved by the Building Official and the Fire Marshal of the City, and which was legally operating as a permitted use in accordance with the Ordinance 3237;
(4) The person was using blank cartridges for a show or theatrical production, or for signal or ceremonial purposes in athletics or sports, or by a military organization;
(5) The person was lawfully defending person or property; or
(6) The person was shooting an air gun, air rifle, BB gun, spring gun or similar gun or device in which the shot, metal pellet or other missile or projectile is propelled by means of compressed air or mechanical spring device, and the person and all projectiles emanating from said gun or device were contained within the person’s premises.
State law references–Authority of municipality regarding firearms and explosives, V.T.C.A., Local Government Code, sec. 229.001; disorderly conduct, V.T.C.A., Penal Code, sec. 42.01; weapons, V.T.C.A., Penal Code, ch. 46; discharge of firearm inside corporate limits of municipality having population of 100,000 or more, V.T.C.A., Penal Code, sec. 42.12.