i have yet to see a leatherman tool not say leatherman on it somewhere.even if there is advertising for another company, it still says leatherman on it too.
One of the easiest ways to determine the quality of a knock off is to try filing your fingernails with the file. That is the hardest product to make on the Leatherman. Ltg files were made in Switzerland and Austria for decades , they bought out the equipment line and started manufacturing in Portland , last I heard they were still bringing them in as not happy with their own quality. Some common other points are the edges of the screwdrivers - crisp and clean? and the hardness of the stainless ( much harder to test ) The Leatherman tools will all say Leatherman