Yeah, I assume that there are 4 K inputs. I mostly matched up the pads on the die shot to the pins, but there are actually 29 pads. The top right pad is segment B, with +9v below it. I can't see an obvious difference between the row and column pads, but if the outputs are just used for the keypad, they don't need much drive, unlike the O output pads at the top of the die.
