@DBZ_universe: Kakuna and Metapod retain the moves of their previous forms.
But here OP says there freshly caught wild pokemon, not trained up from weedle/caterpee.
I think I remember a ton of if not all wild kakuana and metapod in viridian forest only knowing harden. Do some already know poison sting/tackle?
I think Hitsu's right. I remember having to catch a Weedle and Caterpie and train it instead of catching a Kakuna and Metapod because it was a pain to do the old switch and train method early in the game. That's from my Leaf Green experience. I bet Gen 1 had the same move set for freshly caught Pokémon.
This is a stalemate.