No. For starters the Buster Sword is already in the game anyway, but not as an equippable weapon - it is the level 2 physical melee Limit Break.

The weapons sold at Gold Saucer are specifically copies of weapons wielded by actual FFXIV enemies and not characters from past FF games so yeah, unless they appear in FFXIV, I doubt you will ever see such fanservice weapons implemented.

May I be proven wrong though!