You’re talking about 2 different animals.
The HGP Hopper is also called a “Game Plan” Hopper, it looks like cement mixer. Like Pat said they went out of production about 20 or 25 years ago. Most parts for the Game Hoppers are long gone.
The HSH Hopper is the current Hopper that is used in the Bill
changers. Parts for the HSH Hoppers are available.
The HSH and the Game Plan Hoppers are not interchangeable.