I would think you could get more than $600 for some M80v2's with some v3 guts, especially if they are as new as you say. Factory Outlet is 10% off, so I would shoot below that, say closer to $900-1000. If someone offered me $600 for those speakers, that would be like a low blow.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85