You beat me to it. SE cards, are for ONLY the SE, unless of course you have the unobtanium EXPANSE two slot box for the Portable. Recreating one of the would be one hella' hack.
Aspect ratio of the D-Shell connector looks wonky for DB13W3 but that does look like it might be the correct contact on the end. If uncertain about that, check it against the aspect ratio of the DC-37 (floppy drives?) connector.
Doubtful it supports color, more doubtful about the cable connection supporting color. Probably won't work with the Radius Pivot monitor's 640x864 input. Unless you have the Apple Portrait, the only way to use it will be running something like MacPortrait to use a compatible pivoted MutiSync LCD.