No, you don't. You just have to go to the Cave of origin in Sootopolis (ruby&sapphire) and at the bottom most floor you will find groudon(ruby) or kyogre(sapphire). Either one of them will be at lv.45.
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Yes, if playing White Version.
You can catch Articuno on seafoam island whenever you don't have to beat the Pokemon League.
NO (only on ruby)
battle 8 gum and beat elite 4.
You don't awaken him until you beat the elite 4. Then go to the weather institute and they will tell you where to go for each Pokemon KYOGRE/GROUDON.