The five-pound connector mated with the standard trigger spring is what comes out of the box when a private citizen buys most models of Glocks. It is said to have an average pull of 5.5 pounds. In measuring this combo on my G22, Dave got four pounds, 1.5 ounces when the gauge was hooked to the toe of the trigger, and six pounds on the nose when he attached it to the center of the trigger.
A supposed 5.5 pound trigger, which measured from the toe actually was just over 4 pounds in this instance, and from the center, 6 pounds.
Note that the pull measured on this particular gun was a pound and a half lower then the factory spec. Interesting eh?
Trigger pull should be measured at the center of the finger surface of the trigger. Since the Glock's trigger pivots like that of a revolver, it will have an easier pull at the toe of the trigger than at the center of the surface where measurement is normally made. It's simple leverage.