So, neat discovery.

If you look at the textures taken from Dark Forces, you might notice that there are random brown/orange splotches in places they don't seem to fit (they're especially visible on DW_09 and DU_17 through DU-19). After doing some independent research, I've come to the conclusion that they used a modified palette. For starters, Dark Forces has a main default palette and multiple alternate palettes. Normally, only the last three rows are different between them (barring some inconsistency between the versions of gray, brown, and the fullbright colors). For Dark Forces' default palette (often referred to as "SECBASE" due to that being the first level to use it, or "Imperial" in reference to the majority of the levels that use it being Imperial bases), this is 31 shades of metallic blue and 15 shades of pure blue (accompanying the preexisting 15 shades of metallic blue and eight shades of pure blue to add detail and smooth out shading). However, the entirety of Gromas' palette is tinted red-orange to simulate a dusty Mars-ish environment, alongside the three rows of level-specific colors (in this case, deep orange and pale red). But, if you look at the A.D Cop textures taken specifically from Gromas, you can see that they lack this red haze while also not having any visible coloration errors (which would happen if you loaded Gromas' textures with the default palette). I think EMAGSOFT solution to getting Gromas' textures to show up not tinted red was to take the default palette and simply swap out the last three rows for Gromas's level-specific colors. EMAGSOFT then used this modified palette on the rest of the Dark Forces textures, resulting in coloring errors.