No expert mate but as far as i'm aware there's no difference in models.
As for millenium, i got mine from them when they first came out last June and so 1st owner, so the only catch i can see is that you'll be the second owner of a zero miles bike that might have been registered in 2015 but purchased by you in 2016 so will have 12 month less original warranty ( again i'm no expert on this ) or at least loss of warranty period between the original registration date and your purchase date. Worth questioning them about it really for peace of mind.