does it make any difference?
the bottom line is that it does not.
the bottom line is martin van meurs doing 50 knots at southend on a fin that a few minutes before he had run into a mussel bed with- it was scratched and battered and hanging and yet he did 50 knots on it.
If you have a polished fin you can then keep it clean easily, with a wipe over- if you wet sand it it will pick up dirt and crap easily, and hence you will forever be having to wet sand it- so polished is probably easier to look after. But do whatever it probably makes little difference.
The lockheed martin guy talks about the hobie tri foiler and cavitation- i think he is mistaken to call this cavitation, i think its ventilation. He made that mistake so he might easiliy have made others.