Hello CC. Didn't see this until now. Not much to add but conjecture. Both the cavalry style hilt and naval blade were contemporaries from the same period. They appear to likewise be a contemporary melding, not done many years later. Both have a nice, even patina and are fitted well, not some slipshod blacksmith job. I would propose that this assembly might have been made from spare parts as a private purchase piece for a merchantman or privateer. Yes, I know somewhere, there is a sigh of 'not this pirate stuff again from him!', but it does make sense Private purchase were always cast-offs, one-offs or older models reissued for later use. They were used in times of war (this piece nicely fitting into the Napoleonic period) and made at the cheapest cost. The look of this one would have been very appealing to an officer, but it could just as easily been one of a small batch. Common sense tells us an infantryman would never want an anchor on his sword blade, whereas private navies, who had no specific dress code, wouldn't mind the brass hilt and fine (by their standards) styling. I guess I just see maritime in everything!
Mark