There is no such thing as a "mil-spec WEAVER rail".  Weaver rails don't have exact specs.  As Forest once stated, the Weaver rail is more of a "concept" than a "standard."  Thus, ARMS and the US military developed a standardized version of the Weaver concept, which was adopted as Mil-Standard 1913, aka the Picatinny Rail.  Finally, we had a standard, and products that meet the standard can be moved from one gun/mount to another.  The EOTech was designed to fit on the 1913 rail, like just about everything else made today, but it may not fit on many Weaver mounts.  For example, I have a Weaver-brand mount on my Marlin Camp 45, and it would require new cross-slots to be machined onto it in order for an EOTech to mount properly.  This is due to the mount being non-standard, not the EOTech.

-Troy