MidwayUSA and Brownells both have headspace gauges, and you can use your C&R discount.
my understanding is the gauges at Sarco are E. German ones, and the markings are a bit 'obtuse.' My personal recommendation is geta good set of Manson brand gauges (or Pacific Gauges, which is waht my 7.62x39 ones are) and be sure of what is GO and NOGO from the getgo.
The Pacific ones are nice as the GO has a big green stripe aroudn it and the NOGO has a big red strip around it. A little cheaper than the Manson gauges to boot.
If you need 5.45 gauges, order direct from Manson. Fast and reasonable shipping.