I notice that there are many of these scopes selling on eBay by a couple of different sellers for around $240 to $270. The price seems low, is this a good scope, and if so is this a legitimate deal? I can't find the exact same scope anywhere else online. Cabela's has one that is the same except it has the Windplex reticle whereas the eBay scope has the standard Duplex. Cabela's price is $450.