That different models work interchangeably is no surprise. Almost certainly both use a Prolific RS-422 to USB bridge chip, and although they may be different models they probably use the same driver. The output from the GPS
module is NMEA 0183
sentences on all non-Garmin modules AFAIK, so no changes there.
usually doesn't hurt a solid-state circuit, particularly if it is not operating at the time. Salt water
is another issue entirely. While wintering in Gothenberg Sweden
a friend lost
his cell phone
into the marina (on a river); he recovered it a week or two later, dried it out and replaced the battery
- worked just fine. Not something to count on. And I wouldn't have scuba
dived in that freezing water
even with a dry suit, but that is another issue also.