I have a post about this in Hardware. From what I gathered by bugging everyone in the universe about this is that it is a direct replacement for the Fender Narrow Hardtail bridge. I did not end up using it,though, as my body had already been drilled for Fender Vintage style hardtail (wider spacing) so I can not speak from first hand experience.
If you look at the mechanical drawings from both the Warmoth site for the narrow spaced Strat bridge and the StewMac site for the Hipshot, it does not appear as if the holes will line up exactly; the Hipshot shows .416 spacing for string holes and .877 spacing for mounting screws, while the Warmoth dimensions are .424 and .890 respectively. While the differentiation is very small, it seems to me that at least the mounting screw holes being off that much would miss the center of the Warmoth pilot holes drilled and could be problematic
Actually, I have a hipshot hardtail on my hollowbody strat that i just built. I was also concerned about the slight difference in measurements. In the end however, there was no problem. just order the narrow spaced bridge rout ( the one with the larger string thru holes). Awesome bridge BTW. very smooth on the hand and great for palm mutes! :guitaristgif: