1978 Malawi 5 Kwacha WWF Conservation Zebra Proof Silver Coin

Description

This Malawian 5 kwacha silver proof coin was minted in 1978 as part of a collaboration with the World Wildlife Fund and comes with the original certificate of authenticity.  The coin prominently features Burchell's Zebras galloping side-by-side on the reverse and weighs at 28.28g of sterling with a mintage of just over 3600.
The coin displays minimal damage or marring, but the capsule has sustained evident damage.  It seems a few small pieces of dust and debris have made their way in, possibly as a result of the capsule's damage.  I stress that the coin looks unmarred despite this, however I can not guarantee that there isn't something small I'm missing.