The "phone-book bulletproofing" was tested by Mythbusters (Coll. 7; Ep. 8). They proved that the set-up used would protect from small arms fire used in the ambush scene. (Note: but not against heavy weapons like shotgun slugs or high-powered rifles)
Sam Axe (Bruce Campbell) at one point says "You know, for the kids." This is a direct reference to The Hudsucker Proxy (1994) in which Campbell plays a supporting role. The line is a slightly different version of the movie's famous, oft-uttered line: "You know, for kids." Sam says "You know, for THE kids" because he's referring to 2 kids specifically (Corey and Tanya, the kids he's helping out) unlike in 'Hudsucker' where the line refers to kids in general.