These production scraps or 'Progressive Proofs' are likely backdoored by employees or found in dumpsters outside of Fleer. Most likely cut from full sheets - not at the factory. These show different stages of colors added in the printing process.

These are labeled as 'Whiteout' proofs but I'm really not sure about that. More likely the White Scribble or another early coverup layer. The FF is still visible underneath.

Rounded left corner Black Box version.