REDU format ruling
Machine Duplication

Nearest-era rulings (Tengu, Sept 2011) — no REDU-specific archive exists.
Card effect (current official text)Target 1 Machine monster you control with 500 or less ATK; Special Summon up to 2 monsters from your Deck with the same name as that face-up monster.
Rulings
Select 1 face-up Machine-Type monster you control with 500 or less ATK. You can Special Summon up to 2 cards with the same name from your Deck.
- This effect targets 1 face-up Machine-Type monster you control with 500 or less ATK.
- A monster with 500 or less ATk whose Type is Machine by DNA Surgery can be targeted.
- If the target is flipped face-down / leaves the field, you still Special Summon from the Deck.
- If the target has >500 ATK when this effect resolves, you still Special Summon from the Deck.
- If the target is not Machine-Type when this effect resolves, you still Special Summon from the Deck.
- You cannot target a Machine-Type monster if no cards in your Deck share its name (ex: Tokens).
- VS. Proto-Cyber Dragon: You Special Summon up to 2 Cyber Dragons from your Deck while its effect applies, but you can only Special Summon Proto-Cyber Dragon if its effect is negated by (Skill Drain).
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the REDU forum — sourced change requests get reviewed.