Images exist of the 11 footer before its restorations as well as still shots (not frames from episodes) of what the model looked like during production of both pilots as well as the series. These and other behind-the-scenes shots can be compared directly with what the model looks like now.
Such heavy weathering as well as the exaggerated gridlines (as well as lines added that were never there in the first place) can clearly be seen to have not been there when the model was in its prime. I can't believe this is really being contested. The model as it exists now is an erroneous interpretation of what it once was. I won't say it's a defacement because I don't really think that was the restorer's intent. However, altering signage on the model (even if it was normally hard to see) is a blatant change bordering on vandalism. It's near akin to historical texts being tweaked and altered during translation or restoration simply to suit someone's more contemporary agenda.
Repainting, while certainly time and labour intensive is actually a relatively minor issue here I think. The structure of the model is a bigger issue. Should it be moderately repaired and then put on display with appropriate supports (perhaps plexiglass)? Or should it basically be dismantled and some internal components replaced and/or added to better hold everything together? There is also the issue of replacing previous restoration parts that are clearly inaccurate. Sure these won't be original parts (since the originals were lost long ago), but they would be more accurate to those lost parts than what the replacements that are currently there. Also during reconstruction it should be relatively easy enough to restore the original lighting effects.
This isn't an impossible or even a monumental tasks---old items and artifacts are restored/refurbished/reconstructed all the time. The real issue here is will. Fans obviously think this is important, but the real question is whether those presently responsible for the model can be convinced that it is important as well, important enough to act.