solution :-
-open up the texture browser with that dogey texture already selected
-look at the file name underneath the texture
-I can almost garentee it has 'prop' or 'model' before the forwardslash
-look around for an identical texture that doesnt have 'prop' or 'model' before the slash (It almost certainly will be there)
-replace the original one with this new one
-problem fixed
nothing to do with dogey lighting on your part
nothing to do with HDR
everything to do with - the .VMT file used by the texture, theres a little line in it that says "vertexlit" or "lightmappedgeneric". the first will light the texture based on the verticies - good for models. whilst the lightmappedgeneric will use a lightmap - good for walls/floors/ceilings/arches/anything-else-constructed-from-brushes