I don't know anything about these backpacks, but if it's still current issue, you may be able to find one at an off- base military military uniform store. These are usually located next to a military base and they sell current issue gear as well as upgrades. Considering the fact that they are off-base, I would assume that you wouldn't need a Military Issue ID, though if you had a Military Issue ID, you would probably be eligible for a discount on one.
Generally speaking though, the way to tell if it's a copy is to look for the place of manufacture. --If it's made in China, Pakistan, or someplace like that, it's going to be a fake.
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