I've compared the prototype E3 gamepad against the retail version. Nintendo did make some changes after the E3 in 2011 when they exhibited the console. : r/wiiu
Wii U GamePad high-capacity battery now available, promises 8 hours of use - GameSpot
GENUINE OFFICIAL BLACK NINTENDO WII U GAMEPAD | eBay
Buy Nintendo Wii U Wii U GamePad Protector and Stylus Set Retro Mario | eStarland.com
The Wii u gamepad feels so small now compared to the deck! : r/SteamDeck