As Iceberg said, it will work, but there is a possibility that the LNB on the dish is a single polarity model. Does it look something like the one in the attached picture? If so, it is single polarity. To replace it with a dual-polarity model, you would want to remove the waveguide and LNB from the feedhorn as seen in the picture, and replace that assembly by bolting a newer, dual-polarity LNB (such as the Primestar) in its place on the feedhorn.