Pirates used a variety of weapons. The world of Hollywood often portrays pirates using fancy, some time unique weapons. The serrated sword of Dog in Cutthroat Island, and the silver inlaid handled flintlock pistol of Jack Sparrow come instantly to mind.
The possibility that a pirate would decorate his blade or pistol is a reality. Pirates, afterall, had an streak of individualism running through them so there is no reason not to suspect that a pirate would put identifying marks on weapons that belonged to him.
Often the marks would be nothing more that a hash mark but it is conceivable that pirates, like Native Amercians decorated the stocks of rifles or butts of pistols with stones, inlaid metals or what have you. We alos know that gun smiths would creat decorative yet functional weapons for a fee. Many such works are museum quality works today. This is especially true of dueling pistols.
However, it must also be assumed that a pirate, like any person who relied on his weapon fro survival first and foremost wanted a weapon that was sturdy, effecient, and functional. This page explores the aspects of weapons that existed during the Golden Age of Piracy. Some of the weapons are fanciful and probably would have nver been used by the run of the mill pirate. Others are the workhorses of maritime warfare.