Garmin BlueChart question

[cape2fish]

I want to purchase a used Garmin 188c chartplotter and I have two questions.

If I purchase a used unit that was used in another region do I need to purchase a new base map to use it around Cape Cod?

I have heard a rumor that a BlueChart specific to Cape Cod is no longer available from Garmin. Can anyone confirm this? I spoke with the Garmin help line and a BlueChart is available for Cape Cod, map US003R, Garmin # 010-C0017-00. Is there another chart that I am missing? I mostly boat in Buzzards Bay and Vineyard Sound.

Thanks