There are stretches of interstate by my house that I do get what I consider a high-pitch whine but I had it on my previous vehicles with much better tires than our Conti's. In the LR4, it's more muted so I can say it's road noise. I agree with Finlayforprez, if you can take it in and have them drive the same strip with you, that may be a good idea.
Just an FYI, our conti's are not very good tires for tread-life/snow/comfort/noise, compared to say Michelin Latitudes or Bridgestone alenzas in our OEM size. In addition, my LR4 needed an alignment a few months ago that discount tires found and thinks is probably due to belt separation in the tire that they have seen happens with Continental tires more often than other major brands. It doesn't help that these tires are one of the more expensive ones out there for 19".
Keep us posted as I'm interested to see what the dealer says if you decide to take it in.