.308/762X51 headspace gage question

I thought I remember reading somewhere that the .308 round and the 7.62X51 Nato cartridge dimensions are slightly different. Centerfire is sending me my M53(Mg42 type) gun and I have the conversion parts to turn it into a MG3. I have heard(which makes a lot of sense) that it is critical to make sure your bolt and 7.62X51 barrel headspace properly with each other(I always prefer to be safe). So my question is on my Brownell's catalog they only sell the .308 go and no/go gages, is it OK to use these, if not who sells the Nato 7.62X51 spec gages? I also plan on checking my extra 8mm barrels that I have with my 8mm gages.