It is not possible in an unmodded game. The armored Vault 21 jumpsuit was cut from the game and can only be acquired through console commands. The jumpsuit is seen worn by the Courier in the ending credits, tough.
The 21 on the vault 21 jumpsuit is not a font. It is part of the texture of the suit and is not typeable text.
Doc Mitchell gives you a Vault 21 jumpsuit but if you pre ordered the game, you start off with the lightweight leather armor.
Theyre in vault 32
Next to lake Vegas. In between vault 34 and 11
Gary 999 does not exist. First of all; the Gary Vault (Vault 108) is in Fallout 3; not Fallout New Vegas. None of the Gary clones are even mentioned in New Vegas. Secondly, there is no (cannon) Gary 999. The highest (known) numbered Gary is Gary 54.
Vault 34 is located between the East Pump Station and the Gypsum Trian Yard. There is a US military truck near the entrance; which is built into the side of a cliff.
Vault 34 Armory, in a Very Hard locked footlocker on the right side of the weapons storage room.
The unique weapon you want is located in vault 34, the gun is in the armoury there and is called the All-American.
There are 7 vaults as follows: Vault 87 Vault 92 Vault 101 Vault 106 Vault 108 and Vault 112
vault 77 doesn't exist in the game.
There is many hidden quests in Fallout 3 but i there is one when you reenter the vault. (after you father dies) hang around the vault entrance.
SPOILER: no he is in vault 112 in smith Casey garage