Rarely do the gauges truly reflect the manufacturing tolerances of the carburetor or do the inspectors know what really needs to be checked. Here's the drill. His neighbor has a hobby machine shop in his back yard. A carburetor with the proper numbers is found at the local salvage yard. Gauges are made to tight tolerances for venturies, boosters, throttle shafts throttle bores, bleeds and metering plate holes.
Nothing is overlooked.
On race day, enter the carburetor inspector armed with a box of gauges and an attitude that he can walk on water. What a bunch of cheatin' SOBs. When asked for gauge dimensions so competitors can be sure their carburetors are legal, the officials say no way. It's classified information. The inspector made them himself off of the correct carburetor.