Sometimes a couple of pieces of bodywork are situated "just so", and at certain RPMs a kind of harmonic resonance is created when they rub together. I've had it on 2 LTs ('05 and '09), and it has come and gone on both of them. In my case it depended on who did the maintenance, how the pieces were fitted back together, etc. Completely normal.
Definitely the K-Whine. On mine it appears in top gear between 3450 and 3500 RPM. This happens to be at 70MPH so I try to go a bit quicker than that and it goes away.
Just ride and enjoy.
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