Hey, i had a look at it myself, seeing what code reads rarity, and made this which works without modifying every single item's rarity to 1! 
You probably won't need the 2nd code, but it's there for completion's sake.
/edit: Whoops, i meant to edit this into the previous post.
Code:
_C1 Trade all items ON
_L 0xE1020003 0x012A6240
_L 0x20029988 0x24020001
_L 0x212A6240 0x24010001
_C0 Trade all items OFF
_L 0xE1020001 0x012A6240
_L 0x20029988 0x28420003
_L 0x212A6240 0x28410003You probably won't need the 2nd code, but it's there for completion's sake.
/edit: Whoops, i meant to edit this into the previous post.