Not sure if this will help, but there's an eBay auction for an original keypad with wiring somewhat "jacked up"

ebay.com link: Bally 6803 Pinball Replacement ORIGINAL Keypad Strange Science Party Animal

The B,4,5,6 row should correspond to pin position #8 on the Keypad. That's counting over from pin #1 on the far left, when the keypad is facing you and the header pins are at the bottom.

Also just FYI, if you don't mind a bit of solder work I've got DIY Kits for brand new Bally 6803 Keypads here:
http://www.pinitech.com/products/bally6803_keypad.php

Those make it much easier to work with Bally 6803 games that dealing with those original keypads.

Check out Clay's site here.. there's a photo of the Keypad with wire colors somewhat visible.
http://www.pinrepair.com/6803/#keypad

Also a listing of wire colors:
Pin 1 - n/a
Pin 2 - n/a
Pin 3 - Blue/Brown
Pin 4 - Key
Pin 5 - Yellow/white
Pin 6 - Blue (two wires)
Pin 7 - n/a
Pin 8 - Orange/Green
Pin 9 - n/a
Pin 10 - Brown/White (two wires)
Pin 11 - Red/Green (two wires)
Pin 12 - n/a
Pin 13 - Red/White (two wires)
Pin 14 - n/a
Pin 15 - Red (two wires)