While making a card cost more than one type of mana seems obvious, it wasnt something that was present in Magic from the beginning
Dredge is a static ability that introduces a replacement effect

The reconstructed commons sheet for the 1st Edition/Unlimited variant is as follows (the dagger marks indicate that it is not known where the sheet begins or ends): Kabuto, Caterpie, Poliwag, Unown O, Teddiursa, Wooper, Omanyte, Hoppip, Sentret, Unown E, Larvitar, Pineco, Unown I, Dunsparce, Mareep, Spinarak, Energy Ark, Natu, Weedle, Tyrogue, Poliwag, Caterpie, Kabuto, Wooper, Teddiursa, Unown O, Sentret, Hoppip, Omanyte, Larvitar, Unown E, Energy Ark, Unown I, Pineco, Dunsparce, Weedle, Mareep, Tyrogue, Spinarak, Poliwag, Kabuto, Caterpie, Natu, Omanyte, Teddiursa, Wooper, Unown O, Larvitar, Sentret, Unown E, Hoppip, Unown I, Energy Ark, Pineco, Dunsparce, Mareep, Weedle, Tyrogue, Spinarak, Kabuto, Poliwag, Caterpie, Natu, Teddiursa, Omanyte, Wooper, Unown O, Sentret, Larvitar, Unown E, Hoppip, Dunsparce, Energy Ark, Unown I, Spinarak, Pineco, Mareep, Tyrogue, Kabuto, Weedle, Caterpie, Natu, Poliwag, Unown O, Omanyte, Teddiursa, Hoppip, Wooper, Sentret, Larvitar, Unown E, Energy Ark, Pineco, Unown I, Dunsparce, Weedle, Tyrogue, Mareep, Spinarak, Poliwag, Caterpie, Kabuto, Natu, Omanyte, Wooper, Teddiursa, Unown O, Larvitar, Unown E, Sentret, Hoppip, Caterpie, Dunsparce, Unown I, Pineco, Energy Ark, Spinarak, Mareep, Tyrogue, Weedle, Natu The raw data for the holos is as follows (the dashed line is where the transition from H7 to H6 would occur, assuming all boxes in the sample used the same holos sheet

The exact number of copies awarded is unknown, though it is estimated to be fewer than 100