It wouldn't be easy - more importantly, I don't think there'd be any point. In the level files at least, the graphics are stored in 16-bit. Displaying them in 32-bit won't make the slightest bit of difference to them, or any of the other textures.The shading on the 3d polygons might look better, though.
A better patch would be running in higher res. Like I said, not easy though.