I think this is a situation that shows a generation gap in bikers....
today, you buy a high priced part and it fits exactly without any hitches what-so-ever. This was not always the case, and anyone that has experience with 70's, 80's and even 90's bikes and performance parts will not be alarmed that a new part has to be filed to fit.
please do not panic, do not let the "if it's not expensive, it sucks" group of naysayers get you down.
First: call or email customer service, and make sure you have the correct levers. Mistakes happen, and maybe you have the wrong ones....also they may tell you how to fix the problem.
second: compare them to the originals, take a micrometer and measure the thickness of the two levers and file down the new ones. the important part is the pivot point and how well that fits the nut, not the thickness of the perch/housing.
PS: I see lots of chrome on your bike, perhaps your current lever were already filed to fit due to the tighter clearances of the chrome perch.....they should not have much wiggle room.