The proper engineer's answer is yes - make the textures and rename them properly.

The caveat is that if the model doesn't have a  "_t.bmp" texture, but still has reflectivity in FS, it's probably an FSDS2 model, and it handles the naming of the texture slightly different (you don't need the _t).

As regards to the night map "_L", in either case, the MDL file needs to have been prepped to receive a light map.  In building the model, the FSDS user needs to tick off a box when assigning the texture, and the gmax user needs to click a box when producing the model...