Pokemon Base Set 1 Black Triangle Error Booster 3 Pack Lot ART SET - ALL 3 Packs Apparently Heavy ?

Allegedly "Heavy" for the Black Triangle packs are around 20.9 g, as you can see these three weigh in at

20.81 20.90 and 20.99, so there's a good chance all three of these packs are Heavy and contain holos. Without more packs to compare to, it is uncertain.

These Extremely Rare "Black Triangle" Packs are Unlimited or Shadowless Cards in a First Edition Base Set Wrapper That Has Had the 1st Edition Logo Covered by a Black Triangle by a Factory Who Produced the Packs.
This Was Done Because the Company Re-used 1st Edition Wrappers When the Production was Switched Over to the Unlimited Print Run.
These Extremely Rare Packs Have Become a Very Sought After Collectible.