This whole thing is complicated because, as we come into the 18th century, we are coming out of a period--read:all of human history--in which most of style and technology was local, not general. Couple that with the pirate characters that ranged the world, sampling, buying, and stealing their equipment, and you've got a formula for some really dubious "accuracy" debates.
Nam Singh once sent me (ali if you read this, send us the source) a listing of criteria for accuracy used by a group he worked with. It makes sense:
The goods involved:
1) Definitely existed: We have examples or multiple or very detailed illustrations of the goods from the period and location we're portraying.
2) Probably existed: We have drawings and/or descriptions of the goods from the period and location, the technology existed at the time, and similar goods may/did exist in neighboring civilizations at the same time.
3) Possibly existed: The technology existed at the time, similar goods may/did exist in neighboring civilizations, and the goods are a logical extension of usage or style for the culture we portray.
4) Probably did not exist: No pictures or descriptions exist for the time and locale, materials were unlikely to have been available, goods are culturally counterindicated for the group we portray.
5) Definitely did not exist: Technology did not exist at the time, materials used did not exist at the time or were unavailable to the culture, goods are too far out of period.
Anyway, as a test for reenactment accuracy, it works fairly well. :)