I turned down $15k a year ago for mine. I bought NIB in 1997. Game has around 2000-2200 plays, all original except for ColorDMD. Perfectly clean, still looks new even under the playfield.
I would put MM HUO value at at least $12k. I don't think we are going to see pre-MMR levels again, but there cant be more than a handful true HUOs around. And if yours has a Bill Davis PF, then it's really restored - maybe still HUO, but not "original". . (However, some would add to the value just because of the Davis PF).