As per Tommy, it seems that the necks should be spec'd to .560" headstock thickness. As long as yours also checks out that way then no worries.
My strat neck was thicker, dunno why. I put a caliper on this neck last night, didn't do such a great job planing the back as it's ~.570" on the low e end tapering to .550" on the high e end. Now you know that added headstock wood will add magic mojo to the tone-a happy accident like original PAFs.
Its Reranch nitro'd now so I won't know how it sounds or plays for a month or 2.