Looks legit, the stickers don’t stick to the matt anodising very well. As above though you won’t be able to sell it on, so you need to be confident you will stick with 26″ wheels FOREVER!
I don’t think there is a noticeable difference between 26 and 27 it’s more availability of forks etc, though I guess you can use 26″ wheels in 27 forks.
Some seem to have a machined head tube, some don’t.