Hi,
An item of mine which has been tentatively identified as a possible example of an Indian 'cutlass'. Coincidently it has vestiges of black paint or a similar substance on the inside of the guard, on the grip and various spots elsewhere, definitely applied protection of some description or other, whether it was put on specifically for naval use or for protection in general is guesswork.
Regards,
Norman.
P.S. I was always under the impression that in the U.K., rightly or wrongly, that iron/steel items in a naval context, weapons or otherwise, were painted/coated for protection as a matter of course and that this was a long standing mode of preservation dating back to at least the end of the 18thC if not further back than this. In H.M. Forces the adage, 'if it moves salute it if it doesn't paint it' would seem to be appropriate in this context.
