As I understand it it's only for the winners of the specific 4 past auctions, that's why there are only 4 pieces:

Note:

This is the sale for the free editions for the past 4 auction winners. You should have received an email regarding how to proceed to claim your win. Only shipping costs will have to be paid for. If you have not received an email and you were a past auction winner please check your spam folder or email us at - plebsupport@scarce.city to confirm.

Past Auctions:

Hero of Bitcoin Gameboy #3, #5 Auctions

Auction: Hero of Bitcoin Game Boy - Limited Genesis Edition Collector's Package #21 + #1