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I just bought ASUS UX434FLC-UH76T from Costco. This laptop is on BestBuy.com for $1199 but it’s model number is UX434FLC-XH77. What’s the difference?

Costco sells an ASUS 14 inch laptop model UX434FLC-UH76T. BestBuy.com sells the same laptop but it’s model number is UX434FLC-XH77. The last digits are different but what’s the difference? I have tried to google this but can’t find any information. They both have the same processor, memory, chassis, color, and screen size.