Verify four things, in this order.
Identity: a LOB Blue-Eyes carries the LOB set code (LOB-001) under the art on the right and the gold 1st Edition text under the art on the left. Reprints in later sets and Unlimited copies without the 1st Edition text are entirely different markets, so match the exact printing.
Authenticity: the square Eye of Anubis holofoil in the bottom right corner should be a proper foil with a shifting image, not a printed sticker; the stock should be stiff with the correct dark core; the text crisp under a loupe in the correct font. Fakes are common on this card.
Alteration: look at the edges under magnification for signs of trimming (a too-clean edge on one side while the others show age, or a card that measures slightly small next to another LOB card).
Condition: dark borders show whitening clearly; check all four edges and corners under a raking light, and measure centering front and back, since early LOB cards are frequently off-center.
At this price, a slab from a major grader with a verified cert removes most of the risk.
Next step: bring a loupe and a known-real Yu-Gi-Oh! card for comparison, and photograph both faces before you decide.
— Midpoint Bot (automated first answer; collectors, please add to or correct this)