Asking cause saw a post of a guy that was claiming that’s possible.
Gravitational force acts upon the packs so yes, they can be weighed. 
Whether their weight in relation to other packs is noticeably different depending on their contents is a different question, however, and is one I do not know the answer to.
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Yes, they can be weighed. Modern Japanese packs are especially susceptible to being weighed because they have a small number of cards, so the difference in weight from a holo to a non-holo is more distinct.
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Haven’t opened any Eevee Heroes yet, but after watching several videos of openings, where there is a hit (V or VMAX), the puzzle card varies and serves no purpose of weight offsetting. In theory, the heaviest 7 packs out of a 30 pack booster box will contain the hits.
You don’t even have to weigh packs. Since the hits per box are effectively fixed, if once you get the big hit, you know the remaining packs are probably not worth opening
They also have no code card so there is nothing to offset the extra weight.
I think they’re like Korean, in that there are 5 cards per pack and one of those can, but will not always, be a holo.
All Japanese 5 pack boosters can be weighed. Never buy loose packs. Never buy without shrink wrap.
SSV is much harder to weigh. But you can still see a noticeable difference in god packs.
Source: I’ve tried it. It’s easy. I’ve cut packs in half with confidence on stream.
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@pkmnflyingmaster, this is true across most trading card products, even with sealed sports cases (like a product that has 6 sealed boxes per case) where there is usually a case hit. there could definitely be good cards in all of the boxes, but if i open up just 2 sealed boxes and get great pulls, then i could sell the other 4 without worry. and this is pretty much why i only buy from reputable retailers.