Also another thing to note..
Most gfx use the same palette data for 1 level.
So my advice is: If you rip say a sprite from level 1 of a game and set the palette externally, save the image as a bmp and use the "C" command in the sprite ripper to load an external palette. Select the modified bmp and it'll drop the colours in. Hopefully setting the colours for other sprites
note: this method doesn't always work but it worked for Captive (I had to do Captive in various parts, setting a palette and then editing colours of others I missed, after 3 edits I had all 32 colours correct) and also Warzone