Uhhh.... I don't want to come off as the slightest bit argumentative, seeing as how I'm the new kid on the block, but I don't see how anyone, anytime, anywhere could have used a matchlock for hunting. The critters you were after would smell the match, and your ignition time is iffy. Neither of those are considerations if you're in a battalion blasting away at another battalion, but they sure are if you're trying to get the drop on a passel of feral pigs on Hispaniola.
I've hunted hogs (though not with black powder). You could never get close to them with a lit match. Never in perdition. The Spanish were stuck with matchlocks because His Catholic Majesty didn't want his colonies to be better armed than the home crowd. Which is one reason why a bunch of angry Carribbean longhunters were able shoot h*ll out of them, on land and sea. Also: Never seen a period representation of a boucanier with anything but a flinter.
(gets off little soapbox, looks abashed)
Re: the weapon you quote from the Sea Rover's Practice: 57" sounds exactly right for an old-time fusil boucanier, seeing as how the old French inch is about x1.08 longer than our English inch. 54 French inches equal 57" or 58" of ours. So that sounds like a regulation weapon. The bore, on the other hand, sounds English. Curiouser & curiouser... Perhaps it was Dutch? The Dutch used the same big bores as the English did, and favored the same paddlebutt stock and the same ultrasuperlong barrels the French did. I guess without a picture we can't know for sure.
Closest thing I can think of in a ready-made weapon would be the Cookson fowler offered by the Middlesex Trading Co. I looked long & hard at it, but have resolved to build a 12-bore club-butt fowler instead. The buccaneer fusil is a beautiful thing, and I shall build one someday with parts from the Rifle Shoppe, but in the meantime -- as an English subject -- I feel no great need to pass myself off as a counterfeit Frenchman (grins, doffs hat).... and I want to go BP-hunting for the wily wildschwein sometime before 'someday'.
(And then barbecue it, or at least a haunch of it, according to one of Labat's recipes. And then eat it. But that's a whole 'nother topic)