I'm not sure about West
Marine but BoatUS (who also issue domestic MMSI numbers) ask that you have the previous owner contact them to cancel the previous registration--since any
rescue attempt will still be trying to contact the original registrant. Ooops.
The Bahamians probably are familiar enough with US boaters so that they would figure out how to deal with a US domestic number. But technically? You'll need a VHF
license as well, to operate it in foreign waters.