Well, while I apreciate the sentiment, I should point out that period correct is a bit of an issue in and off itself as "pirates" have existed for (and continue to exist) for the better part of 500 years.
They were comprised of Many different ethic and cultural back grounds and to pinpoint what is correct one would have to portray a particular historical figure. Also for the most part every one of the crew members except the captain was most likely little better than a slave...sometimes impressed, sometimes a captive living only because of servitude and very likely to be dressed in little better than rags. The intent here is to have a "costume" that is "real clothing" and not cheap tissue paper and spandex......to wear for one night while handing out candy as a volunteer at the local hospital....also to be period correct one would have to have access to materials other than what is locally available at my towns one and only fabric store (JoAnnes)