IIRC, the DC law that bans carrying a handgun in your home is also the law that bans carrying a handgun on the street. If the SC paints with a broad brush, DC might just become open-carry.
These are the sections of the DC Code being challenged; §§ 22-4504(a) deals with carry. If it is struck down as unconstitutional by the USSC, DC gets instant Vertmont/Alaska carry. § 22-4515 referenced in the code states "Any violation of any provision of this chapter for which no penalty is specifically provided shall be punished by a fine of not more than $1,000 or imprisonment for not more than 1 year, or both."
§§ 7-2502.02(a)(4):
A registration certificate shall not be issued for a …Pistol not validly registered to the current registrant in the District prior to September 24, 1976, except that the provisions of this section shall not apply to any organization that employs at least 1 commissioned special police officer or other employee licensed to carry a firearm and that arms the employee with a firearm during the employee’s duty hours or to a police officer who has retired from the Metropolitan Police Department.
§§ 22-4504(a):
No person shall carry within the District of Columbia either openly or concealed on or about their person, a pistol, without a license issued pursuant to District of Columbia law, or any deadly or dangerous weapon capable of being so concealed. Whoever violates this section shall be punished as provided in § 22-4515, except that:
(1) A person who violates this section by carrying a pistol, without a license issued pursuant to District of Columbia law, or any deadly or dangerous weapon, in a place other than the person’s dwelling place, place of business, or on other land possessed by the person, shall be fined not more than $5,000 or imprisoned for not more than 5 years, or both; or
(2) If the violation of this section occurs after a person has been convicted in the District of Columbia of a violation of this section or of a felony, either in the District of Columbia or another jurisdiction, the person shall be fined not more than $10,000 or imprisoned for not more than 10 years, or both.
§§ 7-2507.02:
Except for law enforcement personnel described in § 7-2502.01(b)(1), each registrant shall keep any firearm in his possession unloaded and disassembled or bound by a trigger lock or similar device unless such firearm is kept at his place of business, or while being used for lawful recreational purposes within the District of Columbia.