This is the "square" form with the player disc with its border still intact. As it came originally in one large fold-up sheet with each disc and its border only attached at four points. This fragile nature means these points often separate when the full sheet is removed from the original game set box.

There are two 1989 versions.
Discs in both have copyright 'MLBPA 1988' on the FRONTS. But BACKS are different.
The first 'A' version has both 'league' and 'team' on BACKS. These text lines were removed in the later "B" version.

Additionally in the 1989 "A" set has several errors. A wrong picture for #32 Barry Larkin (actually teammate Terry McGriff). Also misspelling of #20 Julio Franco (last name as Franko), Roger Clemens (first name as Rodger) and Mark McGwire (last name as McGuire). These mistakes were corrected on the "B" disc versions.

The Beckett Almanac checklists the unnumbered discs alphabetically.