http://www.semicon.panasonic.co.jp/ds4/MN1400_series__J_discon.pdf shows the 28-pin version of the 1400 (slightly different pinout from the 1402). The 1400 in Perfection has 28-pins; my die shot shows 12 un-bonded pads, so it's easy to figure out the numbering.

Even the 16-pin MN1404 has a TST pin! And it only has 6 outputs (CO0-CO5, which I think are strobes, so normally only one active at a time).