I purchased a Navnet 1824c/Nt Vx2 Radar - C-MAP Nt chartplotter from an on-line retailer. The radar is in Canada, being installed on a boat, I am in the US. I am confused about whether the C-MAP charts are pre-installed or not. Some resources say that they are pre-installed, and that I need to buy an unlock code for the region that I will be cruising (Puget Sound area), while other resources say that I need to purchase a C-MAP card to install the appropriate charts. Which is correct?