It is a good deal, IF, it comes with a Nikon USA warranty. The fact that it doesn’t say it comes with a USA warranty is a concern. If it is gray market (Nikon International Warranty), then you don’t have any warranty for all practical purposes. There is no assurance you will ever need the warranty (and I have purchased several camera’s without USA warranty and have NOT regretted it).
I would ask the seller what kind of warranty comes with it. Nikon USA has this combination on sale for $449. List prices in the camera business are even more fictional than new car sticker prices. Obviously a number of people think it is a reasonable deal, since more than 100 have been sold. With a feedback rating of 99.9% this seller is probably legit.