I ordered a QK with a 3/8" gap and its 1/4 at the top near the pin and seems to be 3/8 at the bottom. Im guessing they just bend the bar a little for the 3/8" gap devices?
Nothing is perfect when you are getting down to those measurements but the BOTTOM is the most important. Mature Metal is a very good product though, and if you are unhappy with it just let them know and they WILL fix it. Just shoot them a call. Safe Travels and sorry for the slow reply.... I really haven't been using the site much lately.