This may fall under ITAR if the weapons were select fire and/or restricted to LE/MIL. Not all weapons can be freely transported, especially if it's considered military tech.
A previous article about these guys that was posted here said their weapons were semiautomatic, as well as obtained in Haiti.
If true, that means the article claim about a license was false.
Even if they were semi, many popular optics are restricted by ITAR.