If you have four connectors you don't have a SWM LNB. With this LNB you will have to run two coax cables to the DVR and one to the receiver. If you want to go SWM I would go to Ebay and try to find a SWM LNB, power inserter and splitter. Keep in mind that your signal meter, if you use one, will probably not work with a SWM setup.
If you have a meter with its own power supply you can drop the legacy LNB in the arm and do the setup, and then replace it with the SWM horn. Sounds difficult, but I found this to be the easiest way for me.